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[BUG] #27317
Description
Activity
Found 3 possible duplicate issues:
- [BUG] Cowork tab not showing on Windows 11 Pro x64 — "yukonSilver" marked as unsupported + CoworkVMService cannot be removed #25136
- [BUG] Cowork for windows: yukonSilver not supported #25034
- [BUG] Cowork Windows — macOS diagnostic code paths running on Windows; VM fails to create network endpoint #26751
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🤖 Generated with Claude Code
Same issue here — was working, broke after restart
Cowork was functioning fine for several hours on my machine today (Feb 21, 2026). After a routine system restart, it stopped working entirely and now shows the "Virtualization is not enabled" error.
Environment:
- OS: Windows 11
- Arch: win32/x64
- Claude Desktop: latest version
- Plan: Max
Troubleshooting already performed:
- Enabled Hyper-V via PowerShell ✅
- Installed WSL2 (
wsl --install) — confirmed working,wsl --statusshows Default Version: 2 ✅ - Enabled Virtual Machine Platform via DISM ✅
- Deleted
vm_bundles/claudevm.bundleto force re-download — bundle never re-downloads
Root cause from logs (
cowork_vm_node.log):2026-02-21 11:25:00 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle... 2026-02-21 11:25:04 [warn] [startVM] VM not supported (win32/x64), skippingThe app is classifying my system as
unsupporteddespite all virtualization features being enabled and Cowork having worked on this exact machine hours earlier. The VM bundle is never downloaded, so Cowork cannot start at all.This appears to be the same
yukonSilver not supporteddetection bug described in this issue. No system hardware changes were made — only a routine restart. Please advise.Closing as duplicate of #27316 which was very rapidly fixed in the v1.1.3963 release
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.
- locked as resolved and limited conversation to collaborators
on Mar 1, 2026
Preflight Checklist
What's Wrong?
Cowork VM fails to start on Windows 11 Pro x64 with HYPERVISOR_SERVICE_ERROR / HRESULT 0x80370102 despite Hyper-V being fully enabled and the hypervisor confirmed running via systeminfo. Additionally, the preflight check incorrectly marks yukonSilver as unsupported on a fully capable system. Network diagnostics attempt to run macOS commands (/sbin/ifconfig, /usr/sbin/scutil, /usr/sbin/kextstat) on Windows, all failing with ENOENT.
What Should Happen?
Cowork should detect the active hypervisor, pass the yukonSilver support check, boot the VM successfully, and use Windows-appropriate diagnostic commands (e.g., ipconfig, Get-NetAdapter)
Error Messages/Logs
[error] [VM:start] VM boot failed: HCS operation failed: failed to create compute system: HcsWaitForOperationResult failed with HRESULT 0x80370102: {"Error":-2143878910,"ErrorMessage":"The virtual machine could not be started because a required feature is not installed.","ErrorEvents":[{"Message":"Cannot create system 'cowork-vm' since Hyper-V is not installed on the host."}]} [error] [VM:start] HCS error detected, firmwareVirt=true, sentinel=HYPERVISOR_SERVICE_ERROR [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle... [warn] [startVM] VM not supported (win32/x64), skipping [error] [networkDiagnostics] Failed to run /sbin/ifconfig: spawn /sbin/ifconfig ENOENTSteps to Reproduce
Windows 11 Pro x64, Intel CPU with VT-x and VT-d enabled in BIOS
Enable Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform in Windows Features
Confirm bcdedit /set hypervisorlaunchtype auto
Confirm hypervisor running: systeminfo shows "A hypervisor has been detected"
Install Claude desktop app (Microsoft Store), open Cowork tab
Observe: yukonSilver not supported in preflight, then HRESULT 0x80370102 on every VM boot attempt
App enters infinite retry loop (30+ attempts in logs within minutes)
Claude Model
None
Is this a regression?
I don't know
Last Working Version
No response
Claude Code Version
Claude Desktop 1.1.3918
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
Other
Additional Information
Three distinct bugs in one log: (1) false yukonSilver unsupported detection, (2) HCS 0x80370102 despite active hypervisor, (3) macOS diagnostic paths on Windows
firmwareVirt=true in the newer app version confirms the app detects virtualization at firmware level but still fails at HCS layer
Related issues: #25136, #27010, #25155
Full cowork_vm_node.log available — covers Feb 5 through Feb 21 with hundreds of failed attempts
Attaching the complete log file is recommended