[BUG] Cowork tab missing — yukonSilver "unsupported" on Windows 11 Pro 25H2 Build 26200, i9-13900KF

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?

Cowork tab is completely missing from Claude Desktop. Only "Chat" and "Code" tabs are visible. The cowork_vm_node.log shows yukonSilver not supported (status=unsupported) on every launch — the VM never attempts to boot.

This matches the pattern in #25136, #32004, #32837, #43966, #47327, #48407, #49748, and #50895. Filing to add another confirmed datapoint — none of those issues have received a fix or timeline.

What Should Happen?

Cowork tab should appear alongside Chat and Code. The VM should boot successfully. Windows 11 Pro 25H2 Build 26200 with Hyper-V and all virtualization features enabled is a fully capable and supported configuration.

Error Messages/Logs

From %APPDATA%\Claude\logs\cowork_vm_node.log:

2026-04-15 23:48:00 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-16 00:05:22 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-16 21:34:01 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-16 21:56:31 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-17 11:27:16 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-04-17 11:28:37 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

This is the complete log. The VM never progresses past the platform check. No boot is ever attempted.

Steps to Reproduce

1. Install Claude Desktop (latest, v1.3109.0) on Windows 11 Pro 25H2 (Build 26200.7462)
2. Ensure Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform are all enabled (confirmed via Get-WindowsOptionalFeature)
3. Launch Claude Desktop
4. Observe: only Chat and Code tabs visible — no Cowork tab
5. Check cowork_vm_node.log — shows yukonSilver not supported on loop

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop version: 1.3109.0 (latest)

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

ENVIRONMENT:

• Claude Desktop version: 1.3109.0 (latest)
• OS: Windows 11 Pro 25H2 (Build 26200.7462)
• Processor: 13th Gen Intel Core i9-13900KF, 3000 MHz, 24 Cores, 32 Logical Processors
• RAM: 32 GB
• Motherboard: Gigabyte Z790 UD AC
• BIOS Mode: UEFI
• Secure Boot: On
• Subscription: Pro (paid)
• Install type: Fresh install from claude.ai/download

Virtualization status (all enabled):

• Hyper-V: Enabled (installed via DISM)
• Virtual Machine Platform: Enabled
• Windows Hypervisor Platform: Enabled
• Virtualization-based security: Running

System health:

• DISM /Online /Cleanup-Image /CheckHealth → No component store corruption detected
• sfc /scannow → No integrity violations

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WHAT I'VE TRIED:

1. Enabled Hyper-V via Windows Features GUI — Windows reverted the change on reboot
2. Enabled Hyper-V via DISM /Online /Enable-Feature /FeatureName:Microsoft-Hyper-V-All /All — succeeded, confirmed enabled after reboot
3. Full app quit from system tray and relaunch (multiple times)
4. Full system reboot (multiple times)
5. Clean reinstall of Claude Desktop from claude.ai/download
6. Verified system integrity with DISM and SFC

Nothing resolves it. The platform detection continues to flag yukonSilver as unsupported on a fully capable system.

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ADDITIONAL CONTEXT:
This bug has been reported since February 2026 across at least 8 GitHub issues with no fix shipped. I am a paying Pro subscriber who cannot access a feature included in my plan. The yukonSilver platform detection logic is rejecting systems that meet every stated requirement. Please prioritize this.