diff --git a/src/kits/storage/MimeType.cpp b/src/kits/storage/MimeType.cpp
index 4b4c350867..cf6b6e66cf 100644
--- a/src/kits/storage/MimeType.cpp
+++ b/src/kits/storage/MimeType.cpp
@@ -556,7 +556,7 @@ BMimeType::SetFileExtensions(const BMessage* extensions)
 	if (err == B_OK)
 		err = message.AddInt32("which", B_REG_MIME_FILE_EXTENSIONS);
 
-	if (err != B_OK && extensions != NULL)
+	if (err == B_OK && extensions != NULL)
 		err = message.AddMessage("extensions", extensions);
 
 	if (err == B_OK)