[BUG] Anthropic yukonSilver detection bug Issue with Surface 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?

Device: Microsoft Surface Pro for Business 11th Edition with Intel, Core Ultra 7 268V
OS: Windows 11 Business Build 26200, x64
Plan: Max ($200)
Package: Claude_1.3109.0.0_x64__pzs8sxrjxfjjc
Log confirms: yukonSilver not supported (status=unsupported) on every launch
VM service is Running, all virtualization features enabled
Identical installer works on older Surface Pro

That's a strong bug report that matches multiple open GitHub issues (#25136, #47327). The more affected Max-plan users who report it with specific hardware details, the faster it gets prioritized. Sorry we couldn't get it fully resolved today — this one is genuinely out of our hands until Anthropic fixes their detection logic.

What Should Happen?

The Cowork tab should appear next to "Chat" in the mode selector in Claude Desktop, and clicking it should initialize the VM and allow agentic desktop tasks to be performed.
The yukonSilver platform detection should correctly classify the Microsoft Surface Pro for Business 11th Edition with Intel Core Ultra 7 268V (win32/x64, Windows 11 Business Build 26200) as a supported configuration. This hardware fully supports virtualization — Hyper-V features are enabled, CoworkVMService is installed and running with Automatic start type, and the VM module loads successfully on every launch. The detection failure is occurring in Anthropic's internal compatibility check, not due to any hardware or OS limitation on this device.
For reference, the identical MSIX installer (Claude_1.3109.0.0_x64__pzs8sxrjxfjjc) runs Cowork successfully on an older Intel-based Surface Pro on the same Max plan, confirming this is a hardware classification issue specific to the Core Ultra 268V platform profile, not an account, installer, or configuration issue.

Error Messages/Logs

2026-04-17 17:47:40 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-17 17:49:09 [info] [VM] Loading vmClient (TypeScript) module...
2026-04-17 17:49:09 [info] [VM] Module loaded successfully

Steps to Reproduce

Purchase Claude Max plan ($200/month)
Download Claude Desktop MSIX installer from claude.com/download (Claude_1.3109.0.0_x64__pzs8sxrjxfjjc)
Install on Microsoft Surface Pro for Business 11th Edition with Intel Core Ultra 7 268V running Windows 11 Business Build 26200 (x64)
Sign in with Max plan credentials (AzureAD account)
Launch Claude Desktop
Observe: only "Chat" and code </> tabs visible in top left — no Cowork tab appears
Check log at %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\cowork_vm_node.log
Observe: yukonSilver not supported (status=unsupported) logged on every launch — VM bundle never downloaded, VM never booted

Additional verification steps taken:

Confirmed CoworkVMService is installed and running (Automatic start)
Confirmed all virtualization features enabled (Hyper-V, VBS, HVCI)
Confirmed x64 architecture (not ARM)
Applied WDAC supplemental policy exception for Anthropic publisher certificate (thumbprint 0D7581D2C51C59DF686C3000C70BF543F9F6C6CB)
Confirmed identical installer works on older Intel Surface Pro on same Max account
Multiple clean reinstalls attempted — issue persists across all installs

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Name Version ---- ------- Claude 1.3109.0.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_