[BUG] Cowork shows "Virtual Machine Platform not available" — yukonSilver marked as unsupported on Windows 11 Pro

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?

What's Wrong:
Cowork displays "Virtual Machine Platform not available" and prompts to restart. Restarting never resolves it. The yukonSilver detection check fails on every launch, the VM never initializes, and the vm_bundles folder is never created. This persists through multiple complete clean reinstalls.
Environment:

Device: Dell XPS 15 9520
CPU: Intel Core i7-12700H
RAM: 64GB
OS: Windows 11 Pro 24H2 (Build 26100.7840)
Claude Desktop: Latest MSIX version from claude.ai/download
Install location: %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc
Subscription: Pro

Everything attempted:

Enabled Virtual Machine Platform in Windows Features
Enabled Windows Hypervisor Platform in Windows Features
Enabled Intel VT-x and VT for Direct I/O in BIOS (Dell BIOS, both confirmed ON)
Ran DISM /Online /Enable-Feature /FeatureName:VirtualMachinePlatform /All /LimitAccess
Ran bcdedit /set hypervisorlaunchtype auto
Enabled Developer Mode in Windows Settings
Confirmed CoworkVMService is running
Multiple clean reinstalls including deleting %APPDATA%\Claude, %LOCALAPPDATA%\Claude, running sc delete CoworkVMService
Ran full MSIX package cleanup via PowerShell
Reinstalled as Administrator
Never had Cowork working — fresh install issue, not a regression

Related Issues:
#25136, #27316, #27420, #29887, #32004, #36365, #45715, #47327, #50961

What Should Happen?

Cowork should detect virtualization is enabled and successfully start the VM workspace.

Error Messages/Logs

2026-05-09 16:27:46 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-05-09 16:30:45 [info] [VM] Loading vmClient (TypeScript) module...
2026-05-09 16:30:45 [info] [VM] Module loaded successfully
2026-05-09 16:35:05 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-05-09 16:35:05 [info] [VM] Loading vmClient (TypeScript) module...
2026-05-09 16:35:05 [info] [VM] Module loaded successfully
2026-05-09 17:01:30 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-05-09 17:01:31 [info] [VM] Loading vmClient (TypeScript) module...
2026-05-09 17:01:31 [info] [VM] Module loaded successfully

Steps to Reproduce

Here's exactly what to paste for that field:

Install Claude Desktop (MSIX) from claude.ai/download on Windows 11 Pro 24H2 with administrator privileges
Enable Virtual Machine Platform, Windows Hypervisor Platform, and Hyper-V in Windows Features
Confirm Intel VT-x and VT for Direct I/O are enabled in BIOS
Confirm CoworkVMService is running via PowerShell
Open Claude Desktop and click the Cowork tab
Observe "Virtual Machine Platform not available" error prompting restart
Restart PC — error persists on every subsequent launch
Check %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\cowork_vm_node.log — only yukonSilver unsupported entries, VM never initializes

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude 1.6608.2.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_