[BUG] Stuck in yukonSilver unsupported loop

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?

21TD000PUSJun 15Claude responded: That's a real Lenovo ThinkPad — not a VM.That's a real Lenovo ThinkPad — not a VM. So nested virtualization isn't the issue either.
You've hit a genuine Anthropic bug with no available workaround. Please report it at github.com/anthropics/claude-code/issues with these details:

Model: Lenovo ThinkPad 21TD000PUS
Windows 11 Pro, all Hyper-V features Enabled
CoworkVMService never registers even after clean reinstall as administrator
Stuck in yukonSilver unsupported loop

That's a very specific, reproducible report that should get attention. You can also hit support.anthropic.com if you want direct help rather than a GitHub issue.
Really sorry it didn't resolve — this one is out of your hands.

What Should Happen?

Claude COwork should start on this latest windows PRO 11 workstation. I'd appreciate a linux variant too but that is another feature request.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

Install Claude Desktop (latest version) from claude.ai/download as administrator on Windows 11 Pro (Lenovo ThinkPad 21TD000PUS)
Open Claude Desktop and navigate to the Cowork tab
Observe "Virtual Machine Platform not available" error
Follow the prompt to enable Virtual Machine Platform and restart
Restart PC
Open Claude Desktop → Cowork tab — same error reappears
Verify all virtualization features are enabled via PowerShell (Get-WindowsOptionalFeature): VirtualMachinePlatform, HypervisorPlatform, Microsoft-Hyper-V-All all show Enabled
Uninstall Claude Desktop, delete %APPDATA%\Claude and %LOCALAPPDATA%\Claude, reinstall as administrator
Repeat steps 2–6 — issue persists
Check services.msc — CoworkVMService is never registered

Expected: Cowork initializes the VM workspace normally
Actual: Persistent "Virtual Machine Platform not available" loop. CoworkVMService never appears in services.msc. System is not a VM (Win32_ComputerSystem.Model = 21TD000PUS).

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.12603.1 (3df4fd) 2026-06-11T16:57:36.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_