[BUG] cowork not working

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?

Summary
Cowork tab does not appear in Claude Desktop on Windows 11 Pro x64. The cowork_vm_node.log shows yukonSilver not supported (status=unsupported) on every launch — the VM never attempts to boot.

Environment

• OS: Windows 11 Pro 25H2 (Build 26200.8037)
• CPU: Intel Core i5-4590 @ 3.30 GHz (x64)
• Claude Desktop: v1.3109.0 (35cbf6)
• Subscription: Pro (Annual)
• Installation: Downloaded from claude.com/download (Windows x64, not arm64)

Virtualization status (all confirmed enabled)

• Hyper-V: ✅ enabled (vmms service: Running)
• Hyper-V Hypervisor: ✅ enabled
• Virtual Machine Platform: ✅ enabled
• Hyper-V Services: ✅ enabled
• VT-x enabled in BIOS

Steps to reproduce

1. Install Claude Desktop v1.3109.0 on Windows 11 Pro 25H2
2. Enable all Hyper-V / virtualization features in Windows Features
3. Enable VT-x in BIOS
4. Launch Claude Desktop
5. Observe: only Chat and Code tabs are visible — no Cowork tab

Log output (%APPDATA%\Claude\logs\cowork_vm_node.log)

2026-04-17 19:43:28 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-17 19:43:28 [info] [VM] Loading vmClient (TypeScript) module...
2026-04-17 19:43:28 [info] [VM] Module loaded successfully

This pattern repeats on every launch. The VM never boots.

What I tried

• Full restart of app and system
• Enabled VT-x in BIOS (was previously disabled)
• Enabled all Hyper-V features in Windows Features
• Verified vmms service is Running

Expected behavior
Cowork tab should appear next to Chat and Code in the navigation.

Related issues: #25136, #47327, #48995

What Should Happen?

I should see the cowork tab, since all the pc requirements are being met

Error Messages/Logs

Steps to Reproduce

1. Install Claude Desktop v1.3109.0 on Windows 11 Pro 25H2
2. Enable all Hyper-V / virtualization features in Windows Features
3. Enable VT-x in BIOS
4. Launch Claude Desktop
5. Observe: only Chat and Code tabs are visible — no Cowork tab

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

N/A - Desktop App v1.3109.0 (35cbf6)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_