[BUG] Cowork tab missing on Windows 11 Enterprise x64 — yukonSilver marked "unsupported" despite Hyper-V running

Preflight Checklist

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

What's Wrong?

Cowork tab does not appear in Claude Desktop on Windows 11 Enterprise (23H2, Build 22631.6936). Only "Chat" and "Code" tabs are visible.

Hyper-V is fully enabled and the vmms service is running. The system meets all known requirements.

The Cowork VM log (cowork_vm_node.log) repeats the same error on every app launch:

[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[VM] Loading vmClient (TypeScript) module...
[VM] Module loaded successfully

The VM module loads but the platform check fails, preventing the Cowork tab from appearing and the VM from booting.

Environment:

• Claude Desktop: MSIX install (Claude_pzs8sxrjxfjjc)
• Windows 11 Enterprise 23H2 (Build 22631.6936)
• Architecture: x64
• Hyper-V: Enabled, vmms service running
• Plan: Pro
• Clean reinstall attempted: No change

Related issues: #25136, #25142, #25205, #25692

What Should Happen?

The Cowork tab should appear next to "Chat" and "Code" in the sidebar. The yukonSilver platform check should recognize Windows 11 Enterprise x64 with Hyper-V enabled as a supported configuration. The VM should boot and the Cowork session should start without errors.

Error Messages/Logs

Steps to Reproduce

1. Install Claude Desktop from claude.ai/download on Windows 11 Enterprise x64 (23H2, Build 22631.6936)
2. Ensure Hyper-V is enabled (Get-Service vmms returns Running)
3. Sign in with a Pro plan account
4. Observe that only "Chat" and "Code" tabs appear in the sidebar. No "Cowork" tab.
5. Check the log at %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\cowork_vm_node.log
6. Log shows yukonSilver not supported (status=unsupported) on every launch
7. Quit and reopen the app. Same result. The Cowork tab never appears.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.101

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_