VS Code Fails to Load C# Extension Dependency (ms-dotnettools.csdevkit) on macOS with .NET 9.0 Preview: 'Unable to read package.json'

[T1WiLLi]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version:
• OS Version:

Does this issue occur when all extensions are disabled?: No

• VS Code Version: 1.98.2 and also tested with 1.97.2
• OS Version: macOS (version unknown, e.g., macOS Sequoia 15)

Steps to Reproduce:

1. Install VS Code on macOS (e.g., version 1.98.2).
2. Install the .NET 9.0 preview SDK .
3. Open VS Code and install the C# extension (ms-dotnettools.csharp) & C# Dev kit.
4. Open a .NET project targeting net9.0 (e.g., a project with <TargetFramework>net9.0</TargetFramework> in the .csproj file).
5. Observe the error: Unable to read file '/Users/<username>/.vscode/extensions/ms-dotnettools.csdevkit-1.16.6-darwin-arm64/package.json' (Error: Unable to resolve nonexistent file ...).

Additional Details

• Behavior: The error occurs when the C# extension attempts to load its dependency ms-dotnettools.csdevkit. The package.json file for this extension is missing, suggesting a failed or corrupted installation of the dependency.
• Attempts to Fix:
  • Reinstalled VS Code multiple times, including clearing all user data (~/Library/Application Support/Code, ~/.vscode, and cache directories).
  • Tried older versions of VS Code (e.g., 1.97.2 and 1.98.2), but the issue persists.
  • Deleted the problematic extension folder (~/.vscode/extensions/ms-dotnettools.csdevkit-1.16.6-darwin-arm64) and reinstalled the C# extension, but the error reoccurs.
• Extension Bisect: Using "Help: Start Extension Bisect" confirmed that the issue is caused by the C# extension (ms-dotnettools.csharp), as the error does not occur when this extension is disabled.
• Environment:
  • macOS architecture: ARM64 M2
  • .NET SDK versions installed: 9.0.100-preview.x

Expected Behavior

The C# extension and its dependencies (e.g., ms-dotnettools.csdevkit) should install correctly and load without errors, even when using a preview version of the .NET SDK like .NET 9.0.

Actual Behavior

VS Code displays the error Unable to read file ... package.json for the ms-dotnettools.csdevkit extension, preventing the C# extension from functioning properly. Features like IntelliSense and debugging may not

additional note

VS Code current version on my windows machine works fine.

[T1WiLLi]

After some more testing I pinpointed that the issue seems to happen with dotnet 9.0.104.

Once I updated to 9.0.204, the issue was resolved, it did also happen on my windows machine, but on windows no update were necessary just a quick install / uninstall

[sandy081]

Closing this since the issue seems to be resolved by the user