diff --git a/conformance/README.md b/conformance/README.md
index 2dd922d6..a75ab4f4 100644
--- a/conformance/README.md
+++ b/conformance/README.md
@@ -31,7 +31,7 @@ export OCI_TEST_CONTENT_MANAGEMENT=1
 # Extra settings
 export OCI_HIDE_SKIPPED_WORKFLOWS=0
 export OCI_DEBUG=0
-export OCI_DELETE_MANIFEST_BEFORE_BLOBS=0
+export OCI_DELETE_MANIFEST_BEFORE_BLOBS=0 # defaults to OCI_DELETE_MANIFEST_BEFORE_BLOBS=1 if not set
 ```
 
 Lastly, run the tests:
diff --git a/conformance/setup.go b/conformance/setup.go
index 6395c4b2..379e4850 100644
--- a/conformance/setup.go
+++ b/conformance/setup.go
@@ -310,7 +310,7 @@ func init() {
 	runContentDiscoverySetup = true
 	runContentManagementSetup = true
 	skipEmptyLayerTest = false
-	deleteManifestBeforeBlobs = false
+	deleteManifestBeforeBlobs = true
 
 	if os.Getenv(envVarTagName) != "" &&
 		os.Getenv(envVarManifestDigest) != "" &&
@@ -323,7 +323,9 @@ func init() {
 	}
 
 	skipEmptyLayerTest, _ = strconv.ParseBool(os.Getenv(envVarPushEmptyLayer))
-	deleteManifestBeforeBlobs, _ = strconv.ParseBool(os.Getenv(envVarDeleteManifestBeforeBlobs))
+	if v, ok := os.LookupEnv(envVarDeleteManifestBeforeBlobs); ok {
+		deleteManifestBeforeBlobs, _ = strconv.ParseBool(v)
+	}
 	automaticCrossmountVal := ""
 	automaticCrossmountVal, runAutomaticCrossmountTest = os.LookupEnv(envVarAutomaticCrossmount)
 	automaticCrossmountEnabled, _ = strconv.ParseBool(automaticCrossmountVal)