System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (0x8007000B)

[dibarbet]

Copied from #6842 (comment) by @dkflRus

Using dotnet configured on PATH
Dotnet path: /usr/share/dotnet/dotnet
Activating C# standalone...
Starting server at /home/dkfl/.vscode-oss/extensions/ms-dotnettools.csharp-2.17.7/.roslyn/Microsoft.CodeAnalysis.LanguageServer.dll
Server arguments /home/dkfl/.vscode-oss/extensions/ms-dotnettools.csharp-2.17.7/.roslyn/Microsoft.CodeAnalysis.LanguageServer.dll --logLevel Trace --telemetryLevel off --extensionLogDirectory /home/dkfl/.config/Code - OSS/logs/20240218T102340/window1/exthost/ms-dotnettools.csharp
waiting for named pipe information from server...
[stderr] Unhandled exception. [stderr] System.BadImageFormatException: An attempt was made to load a program with an incorrect format.
 (0x8007000B)
[Error - 10:25:01 AM] Microsoft.CodeAnalysis.LanguageServer client: couldn't create connection to server.
Error: Timeout. Named pipe information not received from server.
	at q.<anonymous> (/home/dkfl/.vscode-oss/extensions/ms-dotnettools.csharp-2.17.7/dist/extension.js:2:1291052)
	at Generator.next (<anonymous>)
	at s (/home/dkfl/.vscode-oss/extensions/ms-dotnettools.csharp-2.17.7/dist/extension.js:2:1280530)

[dibarbet]

@dkflRus this is often a sign of a corrupt dotnet installation or extension installation. Can you paste the output of dotnet --info and which dotnet?

I would also try

1. Completely delete and re-install the C# extension
   a. Uninstall the extension in vscode
   b. Open the extensions folder (there should be an 'open extensions folder' command in vscode)
   c. With the extension uninstalled and vscode closed, delete all the ms-dotnettools.csharp folders in the extension folder
   d. Re-open vscode and re-install.
2. Completely delete and re-install dotnet. The instructions vary depending on platform and how it was installed.

[powellnorma]

I am getting a similar error:

025-04-10 09:42:47.897 [info] Locating .NET runtime version 9.0.1
2025-04-10 09:42:49.777 [info] Did not find .NET 9.0.1 on path, falling back to acquire runtime via ms-dotnettools.vscode-dotnet-runtime
2025-04-10 09:42:49.941 [info] Dotnet path: c:\Users\User\.cursor-server\data\User\globalStorage\ms-dotnettools.vscode-dotnet-runtime\.dotnet\9.0.4~x64\dotnet.exe
2025-04-10 09:42:49.941 [info] Activating C# + C# Dev Kit...
2025-04-10 09:42:50.834 [error] [stderr] Unhandled exception: 
2025-04-10 09:42:50.870 [error] [stderr] System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (0x8007000B)
   at Microsoft.CodeAnalysis.ImmutableArrayExtensions.SelectAsArrayAsync[TItem,TResult](ImmutableArray`1 array, Func`3 selector, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.Options.GlobalOptionService.<GetOptionPersisters>g__GetOptionPersistersAsync|7_1(ImmutableArray`1 persisterProviders, CancellationToken cancellationToken) in /_/src/Workspaces/Core/Portable/Options/GlobalOptionService.cs:line 75
   at Roslyn.Utilities.TaskExtensions.WaitAndGetResult_CanCallOnBackground[T](Task`1 task, CancellationToken cancellationToken) in /_/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Utilities/TaskExtensions.cs:line 56
   at Microsoft.CodeAnalysis.Options.GlobalOptionService.GetOptionPersisters() in /_/src/Workspaces/Core/Portable/Options/GlobalOptionService.cs:line 48
   at Microsoft.CodeAnalysis.Options.GlobalOptionService.SetGlobalOptions(OneOrMany`1 options) in /_/src/Workspaces/Core/Portable/Options/GlobalOptionService.cs:line 192
   at Microsoft.CodeAnalysis.Options.GlobalOptionService.SetGlobalOption(OptionKey2 optionKey, Object value) in /_/src/Workspaces/Core/Portable/Options/GlobalOptionService.cs:line 184
   at Microsoft.CodeAnalysis.Options.GlobalOptionService.SetGlobalOption[T](Option2`1 option, T value) in /_/src/Workspaces/Core/Portable/Options/GlobalOptionService.cs:line 178
   at Program.<<Main>$>g__RunAsync|0_0(ServerConfiguration serverConfiguration, CancellationToken cancellationToken) in /_/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Program.cs:line 107
   at System.CommandLine.CliCommand.<>c__DisplayClass32_0.<<SetAction>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Invocation.InvocationPipeline.InvokeAsync(ParseResult parseResult, CancellationToken cancellationToken)

2025-04-10 09:42:50.887 [info] Language server process exited with 1
2025-04-10 09:42:50.890 [info] [Error - 9:42:51 AM] Microsoft.CodeAnalysis.LanguageServer client: couldn't create connection to server.
2025-04-10 09:42:50.890 [info] Error: Language server process exited unexpectedly
	at ChildProcess.<anonymous> (c:\Users\User\.cursor-server\extensions\ms-dotnettools.csharp-2.69.25-win32-x64\dist\extension.js:1227:18304)
	at ChildProcess.emit (node:events:530:35)
	at ChildProcess._handle.onexit (node:internal/child_process:293:12)

I ran following commands in the integrated vscode/cursor terminal:

> c:\Users\User\.cursor-server\data\User\globalStorage\ms-dotnettools.vscode-dotnet-runtime\.dotnet\9.0.4~x64\dotnet.exe --info

Host:
  Version:      9.0.4
  Architecture: x64
  Commit:       f57e6dc747
  RID:          win-x64

.NET SDKs installed:
  No SDKs were found.

.NET runtimes installed:
  Microsoft.NETCore.App 9.0.4 [C:\Users\User\.cursor-server\data\User\globalStorage\ms-dotnettools.vscode-dotnet-runtime\.dotnet\9.0.4~x64\shared\Microsoft.NETCore.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

system-wide installation of dotnet:

> Get-Command dotnet

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Application     dotnet.exe                                         8.0.23.... C:\Program Files\dotnet\dotnet.exe


> dotnet --info
.NET SDK:
 Version:           8.0.100
 Commit:            57efcf1350
 Workload version:  8.0.100-manifests.8d38d0cc

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22621
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\8.0.100\

.NET workloads installed:
 Workload version: 8.0.100-manifests.8d38d0cc
There are no installed workloads to display.

Host:
  Version:      8.0.0
  Architecture: x64
  Commit:       5535e31a71

.NET SDKs installed:
  8.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

[JoeRobich]

@powellnorma The fix for this issue is dotnet/roslyn#77900 and it should be in the latest release. Please let us know if that resolves your issue.

[powellnorma]

Thank you for the prompt answer. I "solved" this by downgrading to 2.63.32 (which uses c:\Users\User\.cursor-server\data\User\globalStorage\ms-dotnettools.vscode-dotnet-runtime\.dotnet\8.0.15~x64\dotnet.exe). I would love to try the new version, but I am currently hit by cursor/cursor#2832 (comment)

[JoeRobich]

Going to close this as the original issue is resolved.