[BUG] Cowork tab missing — yukonSilver marked as unsupported on Dell Pro Slim Plus QBS1250, Windows 11 Pro x64, all virtualisation features enabled

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?

Environment

• Device: Dell Pro Slim Plus QBS1250
• OS: Windows 11 Pro, Build 26200.8737 (25H2), x64
• Claude Desktop: Latest version from claude.ai/download (clean install)
• Subscription: Pro
• Architecture: x64 (confirmed via PowerShell)

What's Wrong
Cowork tab is not visible in Claude Desktop. Only Chat and Code tabs appear.
CoworkVMService does not register or appear after a clean reinstall.
sc query CoworkVMService returns no output.

Steps Taken (all confirmed completed)

• Full uninstall of Claude Desktop
• Cleared %APPDATA%\Claude and %LOCALAPPDATA%\Claude
• Fresh reinstall from claude.ai/download
• Enabled all required Windows features via DISM:
• VirtualMachinePlatform ✅
• HypervisorPlatform ✅
• Microsoft-Windows-Subsystem-Linux ✅
• Microsoft-Hyper-V-All ✅
• Installed WSL2 (Ubuntu, version 2.7.10) ✅
• Enabled Intel TXT and all virtualisation settings in Dell BIOS ✅
• Restarted PC multiple times throughout

PowerShell Checks

• VirtualizationFirmwareEnabled: FALSE

(Note: Dell Pro Slim Plus QBS1250 BIOS does not expose separate
Intel VT-x toggle — only Intel TXT is available under
Virtualization Support. All available BIOS settings are ON.)

• sc query CoworkVMService: no output (service not registered)
• Get-Service vmms: service not found

Suspected Cause
yukonSilver platform detection incorrectly classifying this Dell
Pro Slim Plus QBS1250 as unsupported. The BIOS on this model does
not expose a standalone Intel Virtualization Technology toggle —
only Intel Trusted Execution Technology (TXT), which is enabled.
This is a known detection gap per issues #25136, #64592, #47327.

Related Issues
#25136, #32004, #47327, #64592, #43966

Impact
Purchased new desktop hardware specifically to run Claude Cowork
for business operations. Unable to use Cowork at all.
Significant time lost troubleshooting a platform-side bug.

What Should Happen?

Cowork tab should be visible and functional in Claude Desktop
on Windows 11 Pro x64 with all virtualisation features enabled.
CoworkVMService should register correctly after a clean MSIX
install. The yukonSilver platform detection should correctly
identify the Dell Pro Slim Plus QBS1250 as a supported platform.

Error Messages/Logs

sc query CoworkVMService — returns no output (service not registered)
Get-Service vmms — service not found
(Get-WmiObject Win32_Processor).VirtualizationFirmwareEnabled — returns False
despite Intel TXT enabled in BIOS (Dell Pro Slim Plus QBS1250 does not 
expose standalone Intel VT-x toggle in BIOS)

Expected log entry never appears:
[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)

Steps to Reproduce

1. Purchase new Dell Pro Slim Plus QBS1250 desktop PC
2. Install Windows 11 Pro (Build 26200.8737)
3. Download and install Claude Desktop from claude.ai/download
4. Open Claude Desktop — Cowork tab is not visible
5. Run sc query CoworkVMService in Admin PowerShell — no output
6. Enable all virtualisation features via DISM (VirtualMachinePlatform,

HypervisorPlatform, WSL, Hyper-V-All)

1. Install WSL2 and Ubuntu
2. Enable Intel TXT in Dell BIOS (only virtualisation option available

on this model)

1. Restart PC
2. Run sc query CoworkVMService — still no output
3. Cowork tab still not visible

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop (Cowork) — not Claude Code CLI. Version unknown — installed from claude.ai/download 02/07/2026

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

This is a Claude Desktop Cowork bug, not a Claude Code CLI issue.
Device: Dell Pro Slim Plus QBS1250.
Related issues: #25136, #32004, #47327, #64592, #43966.
User purchased new desktop hardware specifically to run Cowork
for business operations. Significant time and productivity lost
due to this platform detection bug.