[BUG] Could not find assembly Microsoft.VisualStudio.DesignTools.CodeAnalysis

[AnthonyElcocks]

Describe the Issue

I have followed many 'solutions'. Uninstall/reinstall the extensions
Delete temp folder
Set .net path in options
Used .NET8 and .NET9
Extend the timeout in settings to 60000, and some bigger numbers
Every time I get the following in the C# OUTPUT panel when VS Code starts...

2024-12-13 12:48:22.276 [info] Using dotnet configured on PATH
2024-12-13 12:48:22.278 [info] Dotnet path: C:\Program Files\dotnet\dotnet.exe
2024-12-13 12:48:22.278 [info] Activating C# + C# Dev Kit...
2024-12-13 12:48:24.371 [error] [stderr] Unhandled exception: 
2024-12-13 12:48:24.392 [error] [stderr] System.IO.FileNotFoundException: Could not find assembly Microsoft.VisualStudio.DesignTools.CodeAnalysis, Version=17.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a with code base c:\Projects\Learn C in any extension context.
   at Microsoft.CodeAnalysis.LanguageServer.CustomExportAssemblyLoader.LoadAssemblyFromCodeBase(AssemblyName assemblyName, String codeBaseUriStr) in /_/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/CustomExportAssemblyLoader.cs:line 95
   at Microsoft.VisualStudio.Composition.Reflection.ResolverExtensions.GetManifest(Resolver resolver, AssemblyName assemblyName)
   at Microsoft.VisualStudio.Composition.Reflection.ResolverExtensions.TryUseFastReflection(TypeRef typeRef, Module& manifest)
   at Microsoft.VisualStudio.Composition.Reflection.ResolverExtensions.Resolve(ParameterRef parameterRef)
   at Microsoft.VisualStudio.Composition.ComposedPart.Validate(IReadOnlyDictionary`2 metadataViews)+MoveNext()
   at System.Collections.Generic.List`1.AddRange(IEnumerable`1 collection)
   at Microsoft.VisualStudio.Composition.CompositionConfiguration.Create(ComposableCatalog catalog)
   at Microsoft.CodeAnalysis.LanguageServer.ExportProviderBuilder.CreateExportProviderAsync(ExtensionAssemblyManager extensionManager, IAssemblyLoader assemblyLoader, String devKitDependencyPath, ILoggerFactory loggerFactory) in /_/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/ExportProviderBuilder.cs:line 57
   at Program.<<Main>$>g__RunAsync|0_0(ServerConfiguration serverConfiguration, CancellationToken cancellationToken) in /_/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Program.cs:line 89
   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)

2024-12-13 12:48:24.422 [info] Language server process exited with 1
2024-12-13 12:48:24.432 [info] [Error - 12:48:24 PM] Microsoft.CodeAnalysis.LanguageServer client: couldn't create connection to server.
2024-12-13 12:48:24.432 [info] Error: Language server process exited unexpectedly
    at ChildProcess.<anonymous> (c:\Projects\Learn C#\dot-net-extensions\ms-dotnettools.csharp-2.55.29-win32-x64\dist\extension.js:2:1178170)
    at ChildProcess.emit (node:events:530:35)
    at Process.ChildProcess._handle.onexit (node:internal/child_process:293:12)

Steps To Reproduce

Start VS Code
See error Microsoft.CodeAnalysis.LanguageServer client: couldn't create connection to server.

Expected Behavior

There should be no error when VS Code is started

Environment Information

Windows 11 Enterprise 10.0.261000
VS Code 1.96.0
C# Dev Kit Version 1.14.14

[AnthonyElcocks]

I found my answer...It is because the folder for the project was named Learn C#
Changing it to Learn C Sharp resolved the issue

[AbhitejJohn]

@AnthonyElcocks : Thanks for sharing and glad you were able to unblock as well. Tagging @dibarbet for thoughts on this.

[dibarbet]

Will be resolved in an upcoming prerelease (likely next week)