diff --git a/master_changes.md b/master_changes.md
index d4953ce85b5..b114ee686ca 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -114,6 +114,7 @@ users)
 
 ## Internal
   * Stop using polymorphic comparison when comparing `OpamTypes.switch_selections` [#6102 @kit-ty-kate]
+  * Structured download error types [#6107 @Keryan-dev]
 
 ## Internal: Windows
 
diff --git a/src/client/opamAction.ml b/src/client/opamAction.ml
index da544b35502..da8846cc815 100644
--- a/src/client/opamAction.ml
+++ b/src/client/opamAction.ml
@@ -245,7 +245,7 @@ let download_shared_source st url nvs =
          | None, _ | _, [_] -> ""
          | Some url, _ -> " " ^ OpamUrl.to_string (OpamFile.URL.url url))) url;
   if OpamStateConfig.(!r.dryrun) || OpamClientConfig.(!r.fake)
-  then Done None else
+  then Done (Result ()) else
   let nvs =
     (* filter out version-pinned packages since we already have their source *)
     List.filter (fun nv ->
@@ -259,7 +259,7 @@ let download_shared_source st url nvs =
                OpamFile.OPAM.version_opt) = Some nv.version))
       nvs
   in
-  if nvs = [] then Done None
+  if nvs = [] then Done (Up_to_date ())
   else
   let print_action =
     OpamConsole.msg "%s retrieved %s  (%s)\n"
@@ -290,14 +290,16 @@ let download_shared_source st url nvs =
   OpamProcess.Job.catch (fun e ->
       let na =
         match e with
-        | OpamDownload.Download_fail (s,l) -> (s,l)
-        | e -> (None, Printexc.to_string e)
+        | OpamDownload.Download_fail failure -> failure
+        | e -> Generic_failure
+                 { short_reason = None; long_reason = Printexc.to_string e }
       in
-      Done (Some na))
+      Done (Not_available na))
   @@ fun () ->
   OpamUpdate.download_shared_package_source st url nvs @@| function
-  | Some (Not_available (s, l)), _ ->
-    let msg = OpamStd.Option.default l s in
+  | Some (Not_available failure), _ ->
+    let r = OpamTypesBase.get_dl_failure_reason failure in
+    let msg = OpamStd.Option.default r.long_reason r.short_reason in
     OpamConsole.error "Failed to get sources of %s%s: %s"
       (labelise OpamPackage.to_string)
       (match url, nvs with
@@ -305,34 +307,36 @@ let download_shared_source st url nvs =
        | Some url, _ ->
          Printf.sprintf " (%s)" (OpamUrl.to_string (OpamFile.URL.url url)))
       msg;
-    Some (s, l)
-  | _, ((nv, name, Not_available (s, l)) :: _) ->
-    let msg = match s with None -> l | Some s -> s in
+    Not_available failure
+  | _, ((nv, name, Not_available failure) :: _) ->
+    let r = OpamTypesBase.get_dl_failure_reason failure in
+    let msg = OpamStd.Option.default r.long_reason r.short_reason in
     OpamConsole.error "Failed to get extra source \"%s\" of %s: %s"
       name (OpamPackage.to_string nv) msg;
-    Some (s, l)
+    Not_available failure
   | Some (Result msg), _ ->
-    print_full_action msg; None
+    print_full_action msg; Result ()
   | Some (Up_to_date msg), _ ->
-    print_full_action msg; None
-  | None, [] -> None
+    print_full_action msg; Up_to_date ()
+  | None, [] -> Up_to_date ()
   | None, (e :: es as extras) ->
     if List.for_all (function _, _, Up_to_date _ -> true | _ -> false) extras then
-      print_full_action "cached"
+      (print_full_action "cached";
+       Up_to_date ())
     else
-      (match e, es with
-       | (_, _, Result msg), [] -> print_full_action msg
-       | _, _ ->
-         print_single_actions
-           (List.map (fun (nv, _, _) ->
-                nv,
-                (Printf.sprintf "%d extra sources"
-                   (List.length
-                      (List.filter (fun (nv',_,_) ->
-                           OpamPackage.compare nv nv' = 0)
-                          extras))))
-               extras));
-    None
+      ((match e, es with
+          | (_, _, Result msg), [] -> print_full_action msg
+          | _, _ ->
+            print_single_actions
+              (List.map (fun (nv, _, _) ->
+                   nv,
+                   (Printf.sprintf "%d extra sources"
+                      (List.length
+                         (List.filter (fun (nv',_,_) ->
+                              OpamPackage.compare nv nv' = 0)
+                             extras))))
+                  extras));
+       Result ())
 
 let download_package st nv =
   download_shared_source st
@@ -468,7 +472,9 @@ let prepare_package_source st nv dir =
         (OpamFile.URL.url urlf :: OpamFile.URL.mirrors urlf)
       @@| function
       | Result () | Up_to_date () -> None
-      | Not_available (_,msg) -> Some (Failure msg)
+      | Not_available failure ->
+          let r = OpamTypesBase.get_dl_failure_reason failure in
+          Some (Failure r.long_reason)
     in
     List.fold_left (fun job dl ->
         job @@+ function
diff --git a/src/client/opamAction.mli b/src/client/opamAction.mli
index f355859e18e..b1e57bfc3c8 100644
--- a/src/client/opamAction.mli
+++ b/src/client/opamAction.mli
@@ -21,14 +21,14 @@ open OpamStateTypes
     This doesn't update dev packages that already have a locally cached
     source. *)
 val download_package:
-  rw switch_state -> package -> (string option * string) option OpamProcess.job
+  rw switch_state -> package -> unit download OpamProcess.job
 
 (** [download_same_source_package t url packages]
     As [download_package], download upstream shared source [url] between
     [packages]. *)
 val download_shared_source:
   rw switch_state -> OpamFile.URL.t option -> package list ->
-  (string option * string) option OpamProcess.job
+  unit download OpamProcess.job
 
 (** [prepare_package_source t pkg dir] updates the given source [dir] with the
     extra downloads, overlays and patches from the package's metadata
diff --git a/src/client/opamAdminCommand.ml b/src/client/opamAdminCommand.ml
index 9714372eed6..c7d10c5166b 100644
--- a/src/client/opamAdminCommand.ml
+++ b/src/client/opamAdminCommand.ml
@@ -175,7 +175,8 @@ let package_files_to_cache repo_root cache_dir cache_urls
               checksums
               (OpamFile.URL.url urlf :: OpamFile.URL.mirrors urlf)
             @@| fun r -> match OpamRepository.report_fetch_result nv r with
-            | Not_available (_,m) -> Some m
+            | Not_available failure ->
+              Some failure
             | Up_to_date () | Result () -> None
         in
         error_opt @@| function
@@ -285,8 +286,13 @@ let cache_command cli =
            (OpamPackage.Map.keys errors));
       OpamConsole.errmsg "%s"
         (OpamStd.Format.itemize (fun (nv,el) ->
+             let reasons =
+               List.map (fun e ->
+                   (OpamTypesBase.get_dl_failure_reason e).long_reason)
+                 el
+             in
              Printf.sprintf "[%s] %s" (OpamPackage.to_string nv)
-               (String.concat "\n" el))
+               (String.concat "\n" reasons))
             (OpamPackage.Map.bindings errors))
     );
 
diff --git a/src/client/opamCommands.ml b/src/client/opamCommands.ml
index ff626d7a8b4..fe48fe15768 100644
--- a/src/client/opamCommands.ml
+++ b/src/client/opamCommands.ml
@@ -3336,9 +3336,10 @@ let pin ?(unpin_only=false) cli =
             ~cache_dir:(OpamRepositoryPath.download_cache
                           OpamStateConfig.(!r.root_dir))
             basename pin_cache_dir [] [url] @@| function
-          | Not_available (_,u) ->
+          | Not_available failure ->
+            let r = OpamTypesBase.get_dl_failure_reason failure in
             OpamConsole.error_and_exit `Sync_error
-              "Could not retrieve %s" u
+              "Could not retrieve %s" r.long_reason
           | Result _ | Up_to_date _ ->
             let pkgs =
               OpamAuxCommands.opams_of_dir ?locked ~recurse ?subpath
@@ -3715,8 +3716,10 @@ let source cli =
                   (OpamPackage.to_string nv) dir []
                   [url])
            with
-           | Not_available (_,u) ->
-             OpamConsole.error_and_exit `Sync_error "%s is not available" u
+           | Not_available failure ->
+             let r = OpamTypesBase.get_dl_failure_reason failure in
+             OpamConsole.error_and_exit `Sync_error "%s is not available"
+               r.long_reason
            | Result _ | Up_to_date _ ->
              OpamConsole.formatted_msg
                "Successfully fetched %s development repo to %s\n"
@@ -3726,8 +3729,11 @@ let source cli =
         (let job =
            let open OpamProcess.Job.Op in
            OpamUpdate.download_package_source t nv dir @@+ function
-           | Some (Not_available (_,s)), _ | _, (_, Not_available (_, s)) :: _ ->
-             OpamConsole.error_and_exit `Sync_error "Download failed: %s" s
+           | Some (Not_available failure), _
+           | _, (_, Not_available failure) :: _ ->
+             let r = OpamTypesBase.get_dl_failure_reason failure in
+             OpamConsole.error_and_exit `Sync_error "Download failed: %s"
+               r.long_reason
            | None, _ | Some (Result _ | Up_to_date _), _ ->
              OpamAction.prepare_package_source t nv dir @@| function
              | None ->
diff --git a/src/client/opamPinCommand.ml b/src/client/opamPinCommand.ml
index 3ec2b4731e6..2ddad29759f 100644
--- a/src/client/opamPinCommand.ml
+++ b/src/client/opamPinCommand.ml
@@ -64,8 +64,6 @@ let read_opam_file_for_pinning ?locked ?(quiet=false) name f url =
   >>| OpamFile.OPAM.with_locked_opt locked
 
 
-exception Fetch_Fail of string
-
 let get_source_definition ?version ?subpath ?locked st nv url =
   let root = st.switch_global.root in
   let srcdir = OpamPath.Switch.pinned_package root st.switch nv.name in
@@ -87,11 +85,11 @@ let get_source_definition ?version ?subpath ?locked st nv url =
     | _, _ -> url
   in
   OpamUpdate.fetch_dev_package url srcdir ?subpath nv @@| function
-  | Not_available (_,s) -> raise (Fetch_Fail s)
+  | Not_available _ as err -> err
   | Up_to_date _ | Result _ ->
     let srcdir = OpamFilename.SubPath.(srcdir /? subpath) in
     match OpamPinned.find_opam_file_in_source ?locked nv.name srcdir with
-    | None -> None
+    | None -> Result None
     | Some (f, locked) ->
       match read_opam_file_for_pinning nv.name ?locked f (OpamFile.URL.url url) with
       | None ->
@@ -100,8 +98,8 @@ let get_source_definition ?version ?subpath ?locked st nv url =
             (OpamPath.Switch.Overlay.tmp_opam root st.switch nv.name)
         in
         OpamFilename.copy ~src:(OpamFile.filename f) ~dst;
-        None
-      | Some opam -> Some (fix opam)
+        Result None
+      | Some opam -> Result (Some (fix opam))
 
 let copy_files st opam =
   let name = OpamFile.OPAM.name opam in
@@ -530,16 +528,20 @@ and source_pin
   OpamFilename.remove (OpamFile.filename temp_file);
 
   let opam_opt =
-    try
-      opam_opt >>+ fun () ->
-      urlf >>= fun url ->
+    opam_opt >>+ fun () ->
+    urlf >>= fun url ->
+    match
       OpamProcess.Job.run @@ get_source_definition ?version ?subpath ?locked st nv url
-    with Fetch_Fail err ->
+    with
+    | Result o | Up_to_date o -> o
+    | Not_available failure ->
       if force then None else
         (OpamConsole.error_and_exit `Sync_error
            "Error getting source from %s:\n%s"
            (OpamStd.Option.to_string OpamUrl.to_string target_url)
-           (OpamStd.Format.itemize (fun x -> x) [err]));
+           (OpamStd.Format.itemize (fun x ->
+                (OpamTypesBase.get_dl_failure_reason x).long_reason)
+               [failure]))
   in
   let opam_opt = opam_opt >>| OpamFormatUpgrade.opam_file in
 
@@ -828,9 +830,10 @@ let scan ~normalise ~recurse ?subpath url =
           ~cache_dir:(OpamRepositoryPath.download_cache
                         OpamStateConfig.(!r.root_dir))
           basename pin_cache_dir [] [url] @@| function
-        | Not_available (_,u) ->
+        | Not_available failure ->
+          let r = OpamTypesBase.get_dl_failure_reason failure in
           OpamConsole.error_and_exit `Sync_error
-            "Could not retrieve %s" u
+            "Could not retrieve %s" r.long_reason
         | Result _ | Up_to_date _ ->
           pins_of_dir pin_cache_dir, Some cleanup
       with e -> OpamStd.Exn.finalise e cleanup
diff --git a/src/client/opamSolution.ml b/src/client/opamSolution.ml
index 905d53cd82d..15138eb0efa 100644
--- a/src/client/opamSolution.ml
+++ b/src/client/opamSolution.ml
@@ -20,7 +20,7 @@ module PackageAction = OpamSolver.Action
 module PackageActionGraph = OpamSolver.ActionGraph
 
 
-exception Fetch_fail of string
+exception Fetch_fail of dl_failure
 
 let post_message ?(failed=false) st action =
   match action, failed with
@@ -230,6 +230,8 @@ let display_error (n, error) =
     | Sys.Break | OpamParallel.Aborted -> ()
     | Failure s -> disp "%s" s
     | OpamSystem.Process_error e -> disp "%s" (OpamProcess.string_of_result e)
+    | Fetch_fail failure ->
+      disp "%s" (get_dl_failure_reason failure).long_reason
     | e ->
       disp "%s" (Printexc.to_string e);
       if OpamConsole.debug () then
@@ -632,10 +634,10 @@ let parallel_apply t
               | [] -> None
             in
             OpamAction.download_shared_source t url nvs) @@+ function
-       | None ->
+       | Result () | Up_to_date () ->
          store_time (); Done (`Successful (installed, removed))
-       | Some (_short_error, long_error) ->
-         Done (`Exception (Fetch_fail long_error)))
+       | Not_available failure ->
+         Done (`Exception (Fetch_fail failure)))
 
     | `Build nv ->
       if assume_built && OpamPackage.Set.mem nv requested then
@@ -762,7 +764,9 @@ let parallel_apply t
           ) OpamPackage.Map.empty results in
         if not (OpamPackage.Map.is_empty failed_downloads) then
           OpamJson.append "download-failures"
-            (`O (List.map (fun (nv, err) -> OpamPackage.to_string nv, `String err)
+            (`O (List.map (fun (nv, failure) ->
+                 let err = (get_dl_failure_reason failure).long_reason in
+                 OpamPackage.to_string nv, `String err)
                    (OpamPackage.Map.bindings failed_downloads)));
         (* Report build/install/remove failures *)
         let j =
diff --git a/src/format/opamTypes.mli b/src/format/opamTypes.mli
index 26e818d642d..7c89431068b 100644
--- a/src/format/opamTypes.mli
+++ b/src/format/opamTypes.mli
@@ -48,13 +48,35 @@ type std_path =
   | Lib | Bin | Sbin | Share | Doc | Etc | Man
   | Toplevel | Stublibs
 
+(** Download failure explanation *)
+type dl_fail_reason = {
+  short_reason : string option;
+  long_reason : string;
+}
+(** The usage is: [short_reason] is displayed on normal mode
+    (nothing if [None]), and [long_reason] on verbose mode. *)
+
+(** Tool download failure infos *)
+type 'a dl_tool_failure = {
+  dl_exit_code : int;
+  dl_url : string;
+  dl_reason : 'a;
+}
+
+type curl_error =
+  | Curl_empty_response
+  | Curl_error_response of string
+  | Curl_generic_error of dl_fail_reason
+
+(** Download failure kind *)
+type dl_failure =
+  | Generic_failure of dl_fail_reason
+  | Curl_failure of curl_error dl_tool_failure
+
 (** Download result *)
 type 'a download =
   | Up_to_date of 'a
-  | Not_available of string option * string
-  (** Arguments are respectively the short and long version of an error message.
-      The usage is: the first argument is displayed on normal mode (nothing
-      if [None]), and the second one on verbose mode. *)
+  | Not_available of dl_failure
   | Result of 'a
 
 (** {2 Packages} *)
diff --git a/src/format/opamTypesBase.ml b/src/format/opamTypesBase.ml
index b74e32cd977..0449b54ca6c 100644
--- a/src/format/opamTypesBase.ml
+++ b/src/format/opamTypesBase.ml
@@ -345,3 +345,19 @@ let switch_selections_compare x
 
 let switch_selections_equal x y =
   switch_selections_compare x y = 0
+
+let get_dl_failure_reason = function
+  | Generic_failure r -> r
+  | Curl_failure { dl_exit_code; dl_url; dl_reason } ->
+    let head_msg =
+      Printf.sprintf "curl failure while downloading %s\nExited with code %d\n"
+        dl_url dl_exit_code
+    in
+    match dl_reason with
+    | Curl_empty_response ->
+      { short_reason = Some "curl failure";
+        long_reason = head_msg^"Empty response" }
+    | Curl_error_response e ->
+      { short_reason = Some "curl failure";
+        long_reason = head_msg^"Returned code "^e }
+    | Curl_generic_error r -> { r with long_reason = head_msg^r.long_reason }
diff --git a/src/format/opamTypesBase.mli b/src/format/opamTypesBase.mli
index 068ed269147..bdf46973f2c 100644
--- a/src/format/opamTypesBase.mli
+++ b/src/format/opamTypesBase.mli
@@ -117,3 +117,6 @@ val char_of_separator: separator -> char
 (* Switch selections *)
 val switch_selections_compare : switch_selections -> switch_selections -> int
 val switch_selections_equal : switch_selections -> switch_selections -> bool
+
+(* Download error helper functions *)
+val get_dl_failure_reason : dl_failure -> dl_fail_reason
diff --git a/src/repository/opamDownload.ml b/src/repository/opamDownload.ml
index 482b12eabcf..38f4e36373e 100644
--- a/src/repository/opamDownload.ml
+++ b/src/repository/opamDownload.ml
@@ -14,8 +14,9 @@ open OpamProcess.Job.Op
 
 let log fmt = OpamConsole.log "CURL" fmt
 
-exception Download_fail of string option * string
-let fail (s,l) = raise (Download_fail (s,l))
+exception Download_fail of dl_failure
+let fail failure = raise (Download_fail failure)
+
 
 let user_agent =
   CString (Printf.sprintf "opam/%s" (OpamVersion.(to_string current)))
@@ -93,27 +94,35 @@ let tool_return url ret =
   match Lazy.force OpamRepositoryConfig.(!r.download_tool) with
   | _, `Default ->
     if OpamProcess.is_failure ret then
-      fail (Some "Download command failed",
-                Printf.sprintf "Download command failed: %s"
-                  (OpamProcess.result_summary ret))
+      fail (Generic_failure {
+          short_reason = Some "Download command failed";
+          long_reason = Printf.sprintf "Download command failed: %s"
+              (OpamProcess.result_summary ret); })
     else Done ()
   | _, `Curl ->
-    if OpamProcess.is_failure ret then
-      fail (Some "Curl failed", Printf.sprintf "Curl failed: %s"
-                  (OpamProcess.result_summary ret));
-    match ret.OpamProcess.r_stdout with
-    | [] ->
-      fail (Some "curl empty response",
-                Printf.sprintf "curl: empty response while downloading %s"
-                  (OpamUrl.to_string url))
-    | l  ->
-      let code = List.hd (List.rev l) in
-      let num = try int_of_string code with Failure _ -> 999 in
-      if num >= 400 then
-        fail (Some ("curl error code " ^ code),
-                  Printf.sprintf "curl: code %s while downloading %s"
-                    code (OpamUrl.to_string url))
-      else Done ()
+    let error =
+      if OpamProcess.is_failure ret then
+        Some (Curl_generic_error
+                { short_reason = Some "Curl failed";
+                  long_reason = Printf.sprintf "Curl failed: %s"
+                      (OpamProcess.result_summary ret); })
+      else match ret.OpamProcess.r_stdout with
+        | [] -> Some Curl_empty_response
+        | l  ->
+          let code = List.hd (List.rev l) in
+          let num = try int_of_string code with Failure _ -> 999 in
+          if num >= 400
+          then Some (Curl_error_response code)
+          else None
+    in
+    match error with
+    | Some dl_reason ->
+      fail (Curl_failure
+              { dl_exit_code = ret.OpamProcess.r_code;
+                dl_url = OpamUrl.to_string url;
+                dl_reason;
+              })
+    | None -> Done ()
 
 let download_command ~compress ?checksum ~url ~dst () =
   let cmd, args =
@@ -156,17 +165,20 @@ let really_download
   download_command ~compress ?checksum ~url ~dst:tmp_dst ()
   @@+ fun () ->
   if not (Sys.file_exists tmp_dst) then
-    fail (Some "Downloaded file not found",
-          "Download command succeeded, but resulting file not found")
+    fail (Generic_failure {
+        short_reason = Some "Downloaded file not found";
+        long_reason = "Download command succeeded, but resulting file \
+                       not found"; })
   else if Sys.file_exists dst && not overwrite then
     OpamSystem.internal_error "The downloaded file will overwrite %s." dst;
   if validate &&
      OpamRepositoryConfig.(!r.force_checksums <> Some false) then
     OpamStd.Option.iter (fun cksum ->
         if not (OpamHash.check_file tmp_dst cksum) then
-          fail (Some "Bad checksum",
-                    Printf.sprintf "Bad checksum, expected %s"
-                      (OpamHash.to_string cksum)))
+          fail (Generic_failure {
+              short_reason = Some "Bad checksum";
+              long_reason = Printf.sprintf "Bad checksum, expected %s"
+                      (OpamHash.to_string cksum); }))
       checksum;
   OpamSystem.mv tmp_dst dst;
   Done ()
@@ -301,8 +313,10 @@ module SWHID = struct
     let rec aux max_tries =
       if max_tries <= 0 then
         Done (Not_available
-                (Some (fallback_err "max_tries"),
-                 fallback_err "%d attempts tried; aborting" attempts))
+                (Generic_failure {
+                   short_reason = Some (fallback_err "max_tries");
+                   long_reason = fallback_err "%d attempts tried; aborting"
+                       attempts; }))
       else
         get_dir hash @@+ function
         | Some (`Done fetch_url) -> Done (Result fetch_url)
@@ -310,7 +324,10 @@ module SWHID = struct
           Unix.sleep 10;
           aux (max_tries - 1)
         | None | Some (`Failed | `Unknown) ->
-          Done (Not_available (None, fallback_err "Unknown swhid"))
+          Done (Not_available
+                  (Generic_failure {
+                      short_reason = None;
+                      long_reason = fallback_err "Unknown swhid"; }))
     in
     aux max_tries
 
@@ -342,21 +359,24 @@ module SWHID = struct
                let sources = OpamFilename.Op.(dir / "src") in
                OpamFilename.extract_job archive sources @@| function
                | Some e ->
-                 Not_available (
-                   Some (fallback_err "archive extraction failure"),
-                   fallback_err "archive extraction failure %s"
-                     (match e with
-                      | Failure s -> s
-                      | OpamSystem.Process_error pe ->
-                        OpamProcess.string_of_result pe
-                      | e -> Printexc.to_string e))
+                 Not_available (Generic_failure {
+                   short_reason =
+                     Some (fallback_err "archive extraction failure");
+                   long_reason = fallback_err "archive extraction failure %s"
+                       (match e with
+                        | Failure s -> s
+                        | OpamSystem.Process_error pe ->
+                          OpamProcess.string_of_result pe
+                        | e -> Printexc.to_string e); })
                | None ->
                  (match OpamSWHID.compute sources with
                   | None ->
-                    Not_available (
-                      Some (fallback_err "can't check archive validity"),
-                      fallback_err
-                        "error on swhid computation, can't check its validity")
+                    Not_available (Generic_failure {
+                      short_reason =
+                        Some (fallback_err "can't check archive validity");
+                      long_reason = fallback_err
+                        "error on swhid computation, can't check its validity";
+                    })
                   | Some computed ->
                     if String.equal computed hash then
                       (List.iter (fun (_nv, dst, _sp) ->
@@ -365,23 +385,23 @@ module SWHID = struct
                           dirnames;
                        Result (Some "SWH fallback"))
                     else
-                      Not_available (
-                        Some (fallback_err "archive not valid"),
-                        fallback_err
-                          "archive corrupted, opam file swhid %S vs computed %S"
-                          hash computed)))
+                      Not_available (Generic_failure {
+                        short_reason = Some (fallback_err "archive not valid");
+                        long_reason = fallback_err
+                            "archive corrupted, opam file swhid %S vs \
+                             computed %S" hash computed; })))
           else
-            Done (Not_available
-                    (Some (fallback_err "skip retrieval"),
-                     fallback_err "retrieval refused by user"))
+            Done (Not_available (Generic_failure {
+                    short_reason = Some (fallback_err "skip retrieval");
+                    long_reason = fallback_err "retrieval refused by user"; }))
         else
-          Done (Not_available
-                  (Some (fallback_err "unreachable"),
-                   fallback_err "network failure or API down"))
+          Done (Not_available (Generic_failure {
+                  short_reason = Some (fallback_err "unreachable");
+                  long_reason = fallback_err "network failure or API down"; }))
       else
-        Done (Not_available
-                (Some (fallback_err "no retrieval"),
-                 fallback_err "Download tool permitting post request (%s) not \
-                 set as download tool"
-                   (OpamStd.Format.pretty_list post_tools)))
+        Done (Not_available (Generic_failure {
+                short_reason = Some (fallback_err "no retrieval");
+                long_reason = fallback_err "Download tool permitting \
+                  post request (%s) not set as download tool"
+                    (OpamStd.Format.pretty_list post_tools); }))
 end
diff --git a/src/repository/opamDownload.mli b/src/repository/opamDownload.mli
index 5d936039c90..69d2bf333d1 100644
--- a/src/repository/opamDownload.mli
+++ b/src/repository/opamDownload.mli
@@ -13,7 +13,7 @@ open OpamTypes
 
 (** Configuration init and handling of downloading commands *)
 
-exception Download_fail of string option * string
+exception Download_fail of dl_failure
 
 (** downloads a file from an URL, using Curl, Wget, or a custom configured
     tool, to the given directory. Returns the downloaded filename.
diff --git a/src/repository/opamHTTP.ml b/src/repository/opamHTTP.ml
index 9c62d0ea231..4e6434b21c9 100644
--- a/src/repository/opamHTTP.ml
+++ b/src/repository/opamHTTP.ml
@@ -75,13 +75,20 @@ module B = struct
     OpamProcess.Job.catch
       (fun e ->
          OpamStd.Exn.fatal e;
-         let s,l =
+         let failure =
            let str = Printf.sprintf "%s (%s)" (OpamUrl.to_string remote_url) in
            match e with
-           | OpamDownload.Download_fail (s,l) -> s, str l
-           | _ -> Some "Download failed", str "download failed"
+           | OpamDownload.Download_fail (
+               Generic_failure { short_reason; long_reason = l }) ->
+             Generic_failure { short_reason; long_reason = str l }
+           | OpamDownload.Download_fail failure -> failure
+           | _ ->
+             Generic_failure {
+               short_reason = Some "Download failed";
+               long_reason = str "download failed, "^(Printexc.to_string e);
+             }
          in
-         Done (Not_available (s,l)))
+         Done (Not_available failure))
     @@ fun () ->
     OpamDownload.download ~quiet:true ~overwrite:true ?checksum remote_url dirname
     @@+ fun local_file -> Done (Result (Some local_file))
diff --git a/src/repository/opamLocal.ml b/src/repository/opamLocal.ml
index 77205c0940c..1265559568f 100644
--- a/src/repository/opamLocal.ml
+++ b/src/repository/opamLocal.ml
@@ -78,12 +78,14 @@ let rsync ?(args=[]) ?(exclude_vcdirs=true) src dst =
     ]
   in
   if not(remote || Sys.file_exists src) then
-    Done (Not_available (None, src))
+    Done (Not_available (
+        Generic_failure { short_reason = None; long_reason = src }))
   else if src = dst then
     Done (Up_to_date [])
   else if overlap src dst then
     (OpamConsole.error "Cannot sync %s into %s: they overlap" src dst;
-     Done (Not_available (None, src)))
+     Done (Not_available (
+        Generic_failure { short_reason = None; long_reason = src })))
   else (
     OpamSystem.mkdir dst;
     let convert_path = Lazy.force convert_path in
@@ -91,7 +93,8 @@ let rsync ?(args=[]) ?(exclude_vcdirs=true) src dst =
       ( rsync_arg :: args @ exclude_args @
         [ "--delete"; "--delete-excluded"; convert_path src; convert_path dst; ])
     @@| function
-    | None -> Not_available (None, src)
+    | None -> Not_available (
+        Generic_failure { short_reason = None; long_reason = src })
     | Some [] -> Up_to_date []
     | Some lines -> Result lines
   )
@@ -104,13 +107,18 @@ let rsync_dirs ?args ?exclude_vcdirs url dst =
   if not (is_remote url) &&
      not (OpamFilename.exists_dir (OpamFilename.Dir.of_string src_s))
   then
-    Done (Not_available (None, Printf.sprintf "Directory %s does not exist" src_s))
+    Done (Not_available
+            (Generic_failure {
+                short_reason = None;
+                long_reason = Printf.sprintf
+                    "Directory %s does not exist" src_s; }))
   else
   rsync ?args ?exclude_vcdirs src_s dst_s @@| function
   | Not_available _ as na -> na
   | Result _ ->
     if OpamFilename.exists_dir dst then Result dst
-    else Not_available (None, dst_s)
+    else Not_available (Generic_failure
+                          { short_reason = None; long_reason = dst_s })
   | Up_to_date _ -> Up_to_date dst
 
 let rsync_file ?(args=[]) url dst =
@@ -118,7 +126,8 @@ let rsync_file ?(args=[]) url dst =
   let dst_s = OpamFilename.to_string dst in
   log "rsync_file src=%s dst=%s" src_s dst_s;
   if not (is_remote url || OpamFilename.(exists (of_string src_s))) then
-    Done (Not_available (None, src_s))
+    Done (Not_available (Generic_failure
+                           { short_reason = None; long_reason =  src_s }))
   else if src_s = dst_s then
     Done (Up_to_date dst)
   else
@@ -127,11 +136,13 @@ let rsync_file ?(args=[]) url dst =
      call_rsync (fun () -> Sys.file_exists dst_s)
        ( rsync_arg :: args @ [ convert_path src_s; convert_path dst_s ])
      @@| function
-     | None -> Not_available (None, src_s)
+     | None -> Not_available (Generic_failure
+                                { short_reason = None; long_reason = src_s })
      | Some [] -> Up_to_date dst
      | Some [_] ->
        if OpamFilename.exists dst then Result dst
-       else Not_available (None, src_s)
+       else Not_available (Generic_failure
+                             { short_reason = None; long_reason = src_s })
      | Some l ->
        OpamSystem.internal_error
          "unknown rsync output: {%s}"
@@ -223,12 +234,14 @@ module B = struct
       if OpamFilename.exists filename then res (Some filename)
       else
         Not_available
-          (None, Printf.sprintf
-             "Could not find target file %s after rsync with %s. \
-              Perhaps you meant %s/ ?"
-             (OpamUrl.basename remote_url)
-             (OpamUrl.to_string remote_url)
-             (OpamUrl.to_string remote_url))
+          (Generic_failure {
+              short_reason = None;
+              long_reason = Printf.sprintf
+                  "Could not find target file %s after rsync with %s. \
+                   Perhaps you meant %s/ ?"
+                  (OpamUrl.basename remote_url)
+                  (OpamUrl.to_string remote_url)
+                  (OpamUrl.to_string remote_url); })
 
   let revision _ =
     Done None
diff --git a/src/repository/opamRepository.ml b/src/repository/opamRepository.ml
index f321669e707..81b445aaba3 100644
--- a/src/repository/opamRepository.ml
+++ b/src/repository/opamRepository.ml
@@ -15,6 +15,9 @@ open OpamProcess.Job.Op
 let log fmt = OpamConsole.log "REPOSITORY" fmt
 let slog = OpamConsole.slog
 
+let generic_failure msg =
+  Generic_failure { short_reason = Some msg; long_reason = msg }
+
 
 let find_backend_by_kind = function
   | `http -> (module OpamHTTP.B: OpamRepositoryBackend.S)
@@ -75,7 +78,7 @@ let fetch_from_cache =
           checksums);
     OpamFilename.remove file;
     let m = "cache CONFLICT" in
-    Done (Not_available (Some m, m))
+    Done (Not_available (generic_failure m))
   in
   let dl_from_cache_job root_cache_url checksum file =
     let url = cache_url root_cache_url checksum in
@@ -92,7 +95,8 @@ let fetch_from_cache =
         | None ->
           (OpamLocal.rsync_file url file @@| function
             | Result _ | Up_to_date _-> ()
-            | Not_available (s,l) -> raise (OpamDownload.Download_fail (s,l)))
+            | Not_available failure ->
+              raise (OpamDownload.Download_fail failure))
       end
     | #OpamUrl.version_control ->
       failwith "Version control not allowed as cache URL"
@@ -117,12 +121,16 @@ let fetch_from_cache =
       end else
         mismatch hit_file
   with Not_found -> match checksums with
-    | [] -> let m = "cache miss" in Done (Not_available (Some m, m))
+    | [] ->
+      let m = "cache miss" in
+      Done (Not_available (generic_failure m))
     | checksum::other_checksums ->
       let local_file = cache_file cache_dir checksum in
       let tmpfile = OpamFilename.add_extension local_file "tmp" in
       let rec try_cache_dl = function
-        | [] -> let m = "cache miss" in Done (Not_available (Some m, m))
+        | [] ->
+          let m = "cache miss" in
+          Done (Not_available (generic_failure m))
         | root_cache_url::other_caches ->
           OpamProcess.Job.catch
             (function Failure _
@@ -223,7 +231,7 @@ let pull_from_upstream
     then ret
     else
     let m = "Checksum mismatch" in
-    Not_available (Some m, m)
+    Not_available (generic_failure m)
   | (Result None | Up_to_date None) as ret -> ret
   | Not_available _ as na -> na
 
@@ -239,9 +247,9 @@ let pull_from_mirrors label ?full_fetch ?working_dir ?subpath
       pull_from_upstream label ?full_fetch ?working_dir ?subpath
         cache_dir destdir checksums url
       @@+ function
-      | Not_available (_,s) ->
+      | Not_available (Generic_failure { long_reason; _ }) ->
         OpamConsole.warning "%s: download of %s failed (%s), trying mirror"
-          label (OpamUrl.to_string url) s;
+          label (OpamUrl.to_string url) long_reason;
         aux mirrors
       | r -> Done (url, r)
   in
@@ -252,7 +260,7 @@ let pull_from_mirrors label ?full_fetch ?working_dir ?subpath
       label (OpamUrl.to_string url);
     OpamFilename.rmdir destdir;
     let m = "can't check directory checksum" in
-    url, Not_available (Some m, m)
+    url, Not_available (generic_failure m)
   | ret -> ret
 
 (* handle subpathes *)
@@ -263,11 +271,19 @@ let pull_tree_t
     let fallback success = function
       | None -> success ()
       | Some (Failure s) ->
-        Done (Not_available (Some s, "Could not extract archive:\n"^s))
+        Done (Not_available
+                (Generic_failure {
+                    short_reason = Some s;
+                    long_reason = "Could not extract archive:\n"^s; }))
       | Some (OpamSystem.Process_error pe) ->
-        Done (Not_available (Some (OpamProcess.result_summary pe),
-                             OpamProcess.string_of_result pe))
-      | Some e -> Done (Not_available (None, Printexc.to_string e))
+        Done (Not_available (
+            Generic_failure {
+              short_reason = Some (OpamProcess.result_summary pe);
+              long_reason = OpamProcess.string_of_result pe; }))
+      | Some e -> Done (Not_available
+                          (Generic_failure
+                             { short_reason = None;
+                               long_reason = Printexc.to_string e }))
     in
     match dirnames with
     | [ label, local_dirname, _subpath ] ->
@@ -291,7 +307,9 @@ let pull_tree_t
                    Done (Up_to_date label)
                  with OpamSystem.Process_error r ->
                    Done (Not_available
-                           (Some label, OpamProcess.result_summary r))))
+                           (Generic_failure {
+                              short_reason = Some label;
+                              long_reason = OpamProcess.result_summary r; }))))
             dirnames
         in
         let text =
@@ -310,22 +328,29 @@ let pull_tree_t
             let failing =
               OpamStd.List.filter_map (function
                   | Result _ | Up_to_date _ -> None
-                  | Not_available (Some s,l) -> Some (s,l)
-                  | Not_available (None, _) -> assert false
+                  | Not_available failure -> Some failure
                 ) (copies ())
             in
             if failing = [] then Done (Up_to_date msg) else
             let simple =
               Printf.sprintf "Failed to copy source of %s"
-                (OpamStd.Format.pretty_list (List.map fst failing))
+                (OpamStd.Format.pretty_list (List.map (fun e ->
+                     let r = OpamTypesBase.get_dl_failure_reason e in
+                     OpamStd.Option.default r.long_reason r.short_reason)
+                   failing))
             in
             let long =
               Printf.sprintf "Failed to copy source of:\n%s"
-                (OpamStd.Format.itemize (fun (nv, msg) ->
-                     Printf.sprintf "%s: %s" nv msg)
+                (OpamStd.Format.itemize (fun e ->
+                     let r = OpamTypesBase.get_dl_failure_reason e in
+                     match r.short_reason with
+                     | Some nv ->
+                       Printf.sprintf "%s: %s" nv r.long_reason
+                     | None -> r.long_reason)
                     failing)
             in
-            Done (Not_available (Some simple, long)))
+            Done (Not_available (Generic_failure { short_reason = Some simple;
+                                                   long_reason = long })))
   in
   let label = OpamStd.List.concat_map ", " (fun (x,_,_) -> x) dirnames in
   (match cache_dir with
@@ -336,7 +361,7 @@ let pull_tree_t
    | None ->
      assert (cache_urls = []);
      let m = "no cache" in
-     Done (Not_available (Some m, m)))
+     Done (Not_available (generic_failure m)))
   @@+ function
   | Up_to_date (archive, _) ->
     extract_archive archive "cached"
@@ -350,9 +375,10 @@ let pull_tree_t
     if checksums = [] && OpamRepositoryConfig.(!r.force_checksums = Some true)
     then
       Done (
-        Not_available (
-          Some ("missing checksum"),
-          label ^ ": Missing checksum, and `--require-checksums` was set."))
+        Not_available (Generic_failure {
+            short_reason = Some ("missing checksum");
+            long_reason = label ^ ": Missing checksum, and \
+                                   `--require-checksums` was set."; }))
     else
       OpamFilename.with_tmp_dir_job @@ fun tmpdir ->
       let extract url archive =
@@ -409,7 +435,7 @@ let pull_file label ?cache_dir ?(cache_urls=[])  ?(silent_hits=false)
    | None ->
      assert (cache_urls = []);
      let m = "no cache" in
-     Done (Not_available (Some m, m)))
+     Done (Not_available (generic_failure m)))
   @@+ function
   | Up_to_date (f, _) ->
     if not silent_hits then
@@ -428,15 +454,19 @@ let pull_file label ?cache_dir ?(cache_urls=[])  ?(silent_hits=false)
     then
       Done (
         Not_available
-          (Some "missing checksum",
-           label ^ ": Missing checksum, and `--require-checksums` was set."))
+          (Generic_failure {
+             short_reason = Some "missing checksum";
+             long_reason = label ^ ": Missing checksum, and \
+                                    `--require-checksums` was set."; }))
     else
       OpamFilename.with_tmp_dir_job (fun tmpdir ->
           pull_from_mirrors label cache_dir tmpdir checksums remote_urls
           @@| function
           | _, Up_to_date _ -> assert false
           | _, Result (Some f) -> OpamFilename.move ~src:f ~dst:file; Result ()
-          | _, Result None -> let m = "is a directory" in Not_available (Some m, m)
+          | _, Result None ->
+            let m = "is a directory" in
+            Not_available (generic_failure m)
           | _, (Not_available _ as na) -> na)
 
 let pull_file_to_cache label ~cache_dir ?(cache_urls=[]) checksums remote_urls =
@@ -453,7 +483,9 @@ let pull_file_to_cache label ~cache_dir ?(cache_urls=[]) checksums remote_urls =
         @@| function
         | _, Up_to_date _ -> assert false
         | url, Result (Some _) -> Result (OpamUrl.to_string url)
-        | _, Result None -> let m = "is a directory" in Not_available (Some m, m)
+        | _, Result None ->
+          let m = "is a directory" in
+          Not_available (generic_failure m)
         | _, (Not_available _ as na) -> na)
 
 let packages repo_root =
@@ -607,8 +639,9 @@ let report_fetch_result pkg = function
       (OpamConsole.colorise `green (OpamPackage.to_string pkg))
       msg;
     Up_to_date ()
-  | Not_available (s, l) ->
-    let msg = match s with None -> l | Some s -> s in
+  | Not_available failure as result ->
+    let r = OpamTypesBase.get_dl_failure_reason failure in
+    let msg = match r.short_reason with None -> r.long_reason | Some s -> s in
     OpamConsole.msg "[%s] fetching sources failed: %s\n"
       (OpamConsole.colorise `red (OpamPackage.to_string pkg)) msg;
-    Not_available (s, l)
+    result
diff --git a/src/repository/opamVCS.ml b/src/repository/opamVCS.ml
index b7ef4f8b754..e90be18ccd3 100644
--- a/src/repository/opamVCS.ml
+++ b/src/repository/opamVCS.ml
@@ -84,7 +84,9 @@ module Make (VCS: VCS) = struct
            (OpamFilename.Dir.to_string dirname)
            (OpamUrl.to_string url)
            (match e with Failure fw -> fw | _ -> Printexc.to_string e);
-         Done (Not_available (None, OpamUrl.to_string url)))
+         Done (Not_available (Generic_failure {
+             short_reason = None;
+             long_reason = OpamUrl.to_string url; })))
     @@ fun () ->
     if VCS.exists dirname then
       VCS.clean dirname @@+ fun () ->
diff --git a/src/state/opamFileTools.ml b/src/state/opamFileTools.ml
index 75f25bc6d4d..def9d2be9dc 100644
--- a/src/state/opamFileTools.ml
+++ b/src/state/opamFileTools.ml
@@ -830,8 +830,9 @@ let t_lint ?check_extra_files ?(check_upstream=false) ?(all=false) t =
          | `http ->
            OpamProcess.Job.catch (function
                | Failure msg -> Done (Some msg)
-               | OpamDownload.Download_fail (s,l) ->
-                 Done (Some (OpamStd.Option.default l s))
+               | OpamDownload.Download_fail (
+                   Generic_failure { short_reason; long_reason }) ->
+                 Done (Some (OpamStd.Option.default long_reason short_reason))
                | e -> Done (Some (Printexc.to_string e)))
            @@ fun () ->
            OpamDownload.download ~overwrite:false url dir
@@ -848,8 +849,9 @@ let t_lint ?check_extra_files ?(check_upstream=false) ?(all=false) t =
            OpamLocal.rsync_file url filename
            @@| function
            | Up_to_date f | Result f -> check_checksum f
-           | Not_available (_,src) ->
-             Some ("Source not found: "^src)
+           | Not_available failure ->
+             let r = OpamTypesBase.get_dl_failure_reason failure in
+             Some ("Source not found: "^r.long_reason)
      in
      cond 60 `Error "Upstream check failed"
        ~detail:(OpamStd.Option.to_list upstream_error)
diff --git a/src/state/opamUpdate.ml b/src/state/opamUpdate.ml
index 9fdf0f36750..6ab7e2b4355 100644
--- a/src/state/opamUpdate.ml
+++ b/src/state/opamUpdate.ml
@@ -578,13 +578,13 @@ let download_package_source_t st url nv_dirs =
          dirnames checksums
          (OpamFile.URL.url url :: OpamFile.URL.mirrors url))
       @@+ function
-      | Not_available (_s,_l) as source_result
+      | Not_available _failure as source_result
         when OpamFile.Config.swh_fallback st.switch_global.config ->
         (OpamDownload.SWHID.archive_fallback url dirnames
          @@| function
          | Result None -> Some source_result
          | Result (Some r) -> Some (Result r)
-         | Not_available (s,l) -> Some (Not_available (s,l))
+         | Not_available failure -> Some (Not_available failure)
          | Up_to_date _ -> assert false)
       | source_result -> Done (Some source_result)
   in
diff --git a/tests/reftests/archive.test b/tests/reftests/archive.test
index aa6fcc10680..986c2957fb3 100644
--- a/tests/reftests/archive.test
+++ b/tests/reftests/archive.test
@@ -459,7 +459,7 @@ The following actions will be performed:
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 [ERROR] Failed to get sources of no-checksum.1: missing checksum
 
-OpamSolution.Fetch_fail("no-checksum.1: Missing checksum, and `--require-checksums` was set.")
+no-checksum.1: Missing checksum, and `--require-checksums` was set.
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -493,7 +493,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of multiple-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -513,7 +513,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of multiple-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -552,7 +552,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -572,7 +572,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -628,7 +628,7 @@ The following actions will be performed:
           got      sha256=hash
 [ERROR] Failed to get sources of good-md5-bad-sha256.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -678,7 +678,7 @@ The following actions will be performed:
           got      sha256=hash
 [ERROR] Failed to get sources of good-md5-bad-sha256.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -701,7 +701,7 @@ The following actions will be performed:
           got      sha256=hash
 [ERROR] Failed to get sources of good-md5-bad-sha256.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -740,7 +740,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of good-sha256-bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -760,7 +760,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of good-sha256-bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -815,7 +815,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of clash-with-all-md5s.666: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -881,7 +881,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of clash-with-all-md5s.666: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -904,7 +904,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get sources of clash-with-all-md5s.666: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
diff --git a/tests/reftests/download.test b/tests/reftests/download.test
index d39c21cc1b5..69596a6cec3 100644
--- a/tests/reftests/download.test
+++ b/tests/reftests/download.test
@@ -66,7 +66,9 @@ Processing  1/1: [foo.1: http]
 + curl "--another-args" "3"
 [ERROR] Failed to get sources of foo.1: Curl failed
 
-OpamSolution.Fetch_fail("https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz (Curl failed: \"curl --another-args 3\" exited with code 2)")
+curl failure while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz
+Exited with code 2
+Curl failed: "curl --another-args 3" exited with code 2
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -88,9 +90,11 @@ The following actions will be performed:
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  1/1: [foo.1: http]
 + curl "--another-args" "3"
-[ERROR] Failed to get sources of foo.1: curl error code ***The curl is a lie*** [args: --another-args 3]
+[ERROR] Failed to get sources of foo.1: curl failure
 
-OpamSolution.Fetch_fail("https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz (curl: code ***The curl is a lie*** [args: --another-args 3] while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz)")
+curl failure while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz
+Exited with code 0
+Returned code ***The curl is a lie*** [args: --another-args 3]
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -108,9 +112,11 @@ The following actions will be performed:
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  1/1: [foo.1: http]
 + curl "--write-out" "%{http_code}\n" "--retry" "3" "--retry-delay" "2" "--user-agent" "opam/current" "-L" "-o" "${BASEDIR}/OPAM/download/.opam-switch/sources/foo.1/v1.0.0.tar.gz.part" "--" "https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz"
-[ERROR] Failed to get sources of foo.1: curl error code ***The curl is a lie*** [args: --write-out %{http_code}\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/download/.opam-switch/sources/foo.1/v1.0.0.tar.gz.part -- https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz]
+[ERROR] Failed to get sources of foo.1: curl failure
 
-OpamSolution.Fetch_fail("https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz (curl: code ***The curl is a lie*** [args: --write-out %{http_code}\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/download/.opam-switch/sources/foo.1/v1.0.0.tar.gz.part -- https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz] while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz)")
+curl failure while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz
+Exited with code 0
+Returned code ***The curl is a lie*** [args: --write-out %{http_code}\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/download/.opam-switch/sources/foo.1/v1.0.0.tar.gz.part -- https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz]
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -128,9 +134,11 @@ The following actions will be performed:
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  1/1: [foo.1: http]
 + curl "--another-args" "3"
-[ERROR] Failed to get sources of foo.1: curl error code ***The curl is a lie*** [args: --another-args 3]
+[ERROR] Failed to get sources of foo.1: curl failure
 
-OpamSolution.Fetch_fail("https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz (curl: code ***The curl is a lie*** [args: --another-args 3] while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz)")
+curl failure while downloading https://github.com/UnixJunkie/get_line/archive/v1.0.0.tar.gz
+Exited with code 0
+Returned code ***The curl is a lie*** [args: --another-args 3]
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
diff --git a/tests/reftests/extrasource.test b/tests/reftests/extrasource.test
index fa65a343d65..8905586218a 100644
--- a/tests/reftests/extrasource.test
+++ b/tests/reftests/extrasource.test
@@ -563,7 +563,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of multiple-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -583,7 +583,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of multiple-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -618,7 +618,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -638,7 +638,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -690,7 +690,7 @@ The following actions will be performed:
           got      sha256=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of good-md5-bad-sha256.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -740,7 +740,7 @@ The following actions will be performed:
           got      sha256=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of good-md5-bad-sha256.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -763,7 +763,7 @@ The following actions will be performed:
           got      sha256=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of good-md5-bad-sha256.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -798,7 +798,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of good-sha256-bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -818,7 +818,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of good-sha256-bad-md5.1: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -853,7 +853,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of clash-with-all-md5s.666: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -919,7 +919,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of clash-with-all-md5s.666: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -942,7 +942,7 @@ The following actions will be performed:
           got      md5=hash
 [ERROR] Failed to get extra source "i-am-a-patch" of clash-with-all-md5s.666: Checksum mismatch
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
diff --git a/tests/reftests/shared-fetch.test b/tests/reftests/shared-fetch.test
index 209d951612f..30bfde169c6 100644
--- a/tests/reftests/shared-fetch.test
+++ b/tests/reftests/shared-fetch.test
@@ -271,7 +271,7 @@ The following actions will be performed:
 [ERROR] Failed to get sources of extra.3, intra.3, no-extra.3, out.3 (file://${BASEDIR}/shared.tgz): Checksum mismatch
 -> installed in.3
 
-OpamSolution.Fetch_fail("Checksum mismatch")
+Checksum mismatch
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
diff --git a/tests/reftests/swhid.unix.test b/tests/reftests/swhid.unix.test
index 3b0d6ced65b..326e5241016 100644
--- a/tests/reftests/swhid.unix.test
+++ b/tests/reftests/swhid.unix.test
@@ -39,7 +39,7 @@ The following actions will be performed:
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 [ERROR] Failed to get sources of snappy-ko.2: Download command failed
 
-OpamSolution.Fetch_fail("https://fake.exe/url.tar.gz (Download command failed: \"curl --write-out %{http_code}\\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/fallback/.opam-switch/sources/snappy-ko.2/url.tar.gz.part -- https://fake.exe/url.tar.gz\" exited with code 6)")
+https://fake.exe/url.tar.gz (Download command failed: "curl --write-out %{http_code}\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/fallback/.opam-switch/sources/snappy-ko.2/url.tar.gz.part -- https://fake.exe/url.tar.gz" exited with code 6)
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -68,7 +68,7 @@ The following actions will be performed:
 Processing  1/3: [snappy-swhid-dir.2: http]
 [ERROR] Failed to get sources of snappy-swhid-dir.2: Download command failed
 
-OpamSolution.Fetch_fail("https://fake.exe/url.tar.gz (Download command failed: \"curl --write-out %{http_code}\\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/fallback/.opam-switch/sources/snappy-swhid-dir.2/url.tar.gz.part -- https://fake.exe/url.tar.gz\" exited with code 6)")
+https://fake.exe/url.tar.gz (Download command failed: "curl --write-out %{http_code}\n --retry 3 --retry-delay 2 --user-agent opam/current -L -o ${BASEDIR}/OPAM/fallback/.opam-switch/sources/snappy-swhid-dir.2/url.tar.gz.part -- https://fake.exe/url.tar.gz" exited with code 6)
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -132,7 +132,7 @@ The following actions will be performed:
 Source https://fake.exe/url.tar.gz is not available. Do you want to try to retrieve it from Software Heritage cache (https://www.softwareheritage.org)? It may take few minutes. [y/n] y
 [ERROR] Failed to get sources of snappy-swhid-ko.2: SWH fallback: Unknown swhid
 
-OpamSolution.Fetch_fail("SWH fallback: Unknown swhid")
+SWH fallback: Unknown swhid
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -152,7 +152,7 @@ The following actions will be performed:
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 [ERROR] Failed to get sources of snappy-swhid-ko.2: SWH fallback: no retrieval
 
-OpamSolution.Fetch_fail("SWH fallback: Download tool permitting post request (wget and curl) not set as download tool")
+SWH fallback: Download tool permitting post request (wget and curl) not set as download tool
 
 
 <><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>