Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

[BUG] Cowork tab not showing on Windows 11 Pro x64 — "yukonSilver" marked as unsupported + CoworkVMService cannot be removed

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report
• I am using the latest version of Claude Desktop

What's Wrong?

After installing the latest Claude Desktop for Windows (v1.1.2685.0, downloaded Feb 11, 2026), the Cowork tab does not appear at all. Only "Chat" is available. The root cause appears to be two interrelated issues:

1. yukonSilver VM configuration is marked as "unsupported" — preventing the VM bundle from being downloaded and the Cowork tab from appearing.
2. CoworkVMService cannot be removed — the installer detects it as a "conflicting service" but fails to remove it with "Access is denied", even when running as Administrator.

Environment

Symptoms

• Cowork tab is not visible in Claude Desktop — only Chat mode available
• vm_bundles folder under %APPDATA%\Claude is never created
• Regular Chat mode works without issues

Log Evidence

cowork_vm_node.log

2026-02-11 18:01:09 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

This appears to be the primary issue: the VM configuration yukonSilver is incorrectly classified as "unsupported" on a fully capable x64 Windows 11 Pro system with all virtualization features enabled.

ClaudeSetup.log (repeated across multiple installation attempts)

WARNING: CoworkVMService already exists (potential conflict)
Conflicting service: true
Removing conflicting CoworkVMService...
WARNING: failed to remove conflicting service: could not open CoworkVMService: Access is denied.
WARNING: old package removal had issues: exit status 1

The installer successfully installs the MSIX package (INSTALL_SUCCESS), but:

• Cannot remove the pre-existing CoworkVMService (Access denied even with full elevation)
• Cannot remove previous MSIX package cleanly (exit status 1)
• Launches via explorer.exe claude:// which fails because the protocol handler is not registered

Manual removal also fails

# As Administrator:
sc.exe delete CoworkVMService
# Result: [SC] OpenService FEHLER 5: Zugriff verweigert (Access denied)

The service cannot be removed even via Administrator PowerShell or registry manipulation.

Additional Installation Issue

The installer has a user account elevation conflict: When run by a non-admin user (e.g., "Fritz") and elevated to a different admin account (e.g., "Admin"), the MSIX is downloaded and installed in the Admin user's context (C:\Users\Admin\AppData\Local\Temp\), making it invisible to the original user. The app does not appear in the non-admin user's Start menu.

Workaround found: Running Add-AppxPackage manually as the target user installs the MSIX correctly for that user.

Steps to Reproduce

1. Install Claude Desktop from claude.ai/download on Windows 11 Pro x64 (Build 26200)
2. Ensure all virtualization features are enabled (Hyper-V, VMP, WHP, WSL2)
3. Launch Claude Desktop
4. Observe: Only "Chat" tab visible, no "Cowork" tab
5. Check %APPDATA%\Claude\logs\cowork_vm_node.log for "yukonSilver not supported"
6. Check %LOCALAPPDATA%\Temp\ClaudeSetup.log for CoworkVMService access denied warnings

Expected Behavior

• Cowork tab should be visible and functional on Windows 11 Pro x64 with all virtualization features enabled
• yukonSilver should be recognized as supported on this configuration
• Installer should be able to clean up its own services
• MSIX should install for the user who initiated the setup, not the elevation account

Suggested Fixes

1. Review yukonSilver platform detection logic — x64 Windows 11 Pro with Hyper-V should not be classified as "unsupported"
2. Fix CoworkVMService permissions — the service should be removable by the installer or at minimum by a system administrator
3. Fix user context for MSIX installation — when elevating to a different admin account, install the package for the original user
4. Register claude:// protocol handler during MSIX installation so the post-install launch works
5. Add a manual "Reset Cowork" option in the app settings to allow users to clean up stale services and VM bundles

What Should Happen?

Claude should be installed completely and correctly

Error Messages/Logs

See above (sorry, I'm first time here

Steps to Reproduce

Steps to Reproduce

Install Claude Desktop from claude.ai/download on Windows 11 Pro x64 (Build 26200)
Ensure all virtualization features are enabled (Hyper-V, VMP, WHP, WSL2)
Launch Claude Desktop
Observe: Only "Chat" tab visible, no "Cowork" tab
Check %APPDATA%\Claude\logs\cowork_vm_node.log for "yukonSilver not supported"
Check %LOCALAPPDATA%\Temp\ClaudeSetup.log for CoworkVMService access denied warnings

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

1.1.2685

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

No response