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[BUG] Cowork tab not showing on Windows 11 Pro x64 — "yukonSilver" marked as unsupported + CoworkVMService cannot be removed #25136
Description
Activity
Found 2 possible duplicate issues:
- [BUG] Cowork for windows: yukonSilver not supported #25034
- [BUG] Cowork Windows - MSIX installs for elevating admin user, not calling standard user (split-account enterprise environment) #25055
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🤖 Generated with Claude Code
I received the following from Claude:
The problem is definitely the Windows Insider build 26200. Cowork's compatibility detection doesn't recognize this preview build as supported, even though your system has all the right features.
Same issue here — yukonSilver marked unsupported on Windows 11 Pro Insider Preview x64
Environment
- Claude Desktop Version: 1.1.2998
- OS: Windows 11 Pro Insider Preview, Build 26300, 25H2
- CPU: 11th Gen Intel Core i7-1185G7 @ 3.00GHz (x64)
- RAM: 64 GB
- Hyper-V: VM Monitor Mode Extensions: Yes; Virtualization Enabled In Firmware: Yes
- Subscription: Pro
Symptoms
Cowork tab does not appear — only Chat and Code tabs visible
Log Output (
%APPDATA%\Claude\logs\cowork_vm_node.log)Every launch produces the same result:
2026-01-23 01:12:13 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...VM module loads successfully but yukonSilver is still classified as unsupported:
2026-02-13 08:01:50 [info] [VM] Loading vmClient (TypeScript) module... 2026-02-13 08:01:50 [info] [VM] Module loaded successfully 2026-02-13 08:07:32 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...There's a new installer out, the problem seems to be fixed.
I used the installer but had granted the normal user admin rights. The Cowork Tab now shows up.
The Version I installed is Claude 1.1.2998 (1f1d4d) 2026-02-12T20:50:41.000Z
Same issue here — yukonSilver marked unsupported on Windows 11 Business x64
Environment
Claude Desktop Version: 1.1.2998 (1f1d4d)
OS: Windows 11 Business Version 25H2
CPU: Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz (1.50 GHz)
System Type: 64-bit operating system, x64-based processor
RAM: 64 GB
Hyper-V: VM Monitor Mode Extensions: Yes; Virtualization Enabled In Firmware: Yes
Subscription: Pro
Symptoms
Cowork tab does not appear — only Chat and Code tabs visibleLog Output (%APPDATA%\Claude\logs\cowork_vm_node.log)
Experiencing the same issue. Cowork tab does not appear — only Chat and Code are visible.
Environment:
- Claude Desktop: v1.1.2685 (f39a62)
- Windows 11 Enterprise 25H2, Build 26200.7623
- HP ZBook Power 16 inch G11 Mobile Workstation
- Intel Core Ultra 9 185H (2.30 GHz)
- 64GB RAM, x64-based processor
- Team plan (premium seat), Cowork confirmed enabled by org admin
Virtualization features (all enabled, confirmed after reboot):
- Hyper-V ✅
- Virtual Machine Platform ✅
- Windows Hypervisor Platform ✅
No conflicting service:
C:\Windows\System32>sc query CoworkVMService [SC] EnumQueryServicesStatus:OpenService FAILED 1060: The specified service does not exist as an installed service.Log output (
%APPDATA%\Claude\logs\cowork_vm_node.log):2026-01-23 18:45:42 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...This has been repeating on every app launch am on latest version and have tried reinstall
Troubleshooting attempted:
- Signed out and back in
- Full app restart
- Reinstalled latest version as admin
- Enabled all virtualization features and rebooted
- Confirmed Cowork enabled by Team org admin
- Contacted Anthropic support (bot only, no resolution)
This is a corporate-managed machine but with full admin rights and all virtualisation features available and enabled. The VM support check appears to be incorrectly returning "unsupported" for this configuration.
cowork_vm_node.log - same here
I'm experiencing the same issue. Cowork tab does not appear in Claude Desktop.
Environment:
- Claude Desktop: v1.1.3189 (1b7b58)
- OS: Windows 11 Pro 25H2 (Build 26200.7840), x64
- CPU: Intel Core Ultra 9 285K (3.70 GHz)
- RAM: 48 GB
- Plan: Pro (monthly)
Virtualization features (all Enabled):
- Hyper-V (all sub-components)
- HypervisorPlatform
- VirtualMachinePlatform
Log output (
%APPDATA%\Claude\logs\cowork_vm_node.log):The issue has been persistent since January 26, 2026. Initially the log showed
ERR_MODULE_NOT_FOUNDfor@ant/claude-swift, which was resolved in a later app update. Since February 13, the VM module loads successfully, but the VM still refuses to start:[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle... [warn] [startVM] VM not supported (win32/x64), skipping [info] [VM] Loading vmClient (TypeScript) module... [info] [VM] Module loaded successfullyEnabling Hyper-V, HypervisorPlatform, and VirtualMachinePlatform + rebooting did not resolve the issue. The
yukonSilverconfiguration remains marked as unsupported despite a fully capable x64 system with all virtualization features enabled.Same problem on
windows 10 pro
claude Claude 1.1.3189 (1b7b58) 2026-02-14T00:09:46.000Z
Plan: Pro (monthly)Проблема актуальна:
Claude 1.1.3189 (1b7b58) 2026-02-14T00:09:46.000Z
windows 11 pro24 remaining items
Cowork: yukonSilver marked as unsupported on Windows 11 Pro x64 — VM not supported (win32/x64)
Environment:OS: Windows 11 Pro, Version 24H2, Build 26100.4946
Architecture: x64
Claude Desktop: v1.1.3918.0 (MSIX install from claude.com/download)
Install type: WindowsApps (MSIX package)Virtualization status (all confirmed enabled):
CPU Virtualization: Enabled (confirmed in Task Manager)
Hyper-V: Enabled
Virtual Machine Platform: Enabled
Windows Hypervisor Platform: Enabled
bcdedit /enum shows: hypervisorlaunchtype Auto
Get-Service | findstr -i cowork shows: Running CoworkVMService ClaudeWhat's wrong:
Cowork tab shows "Virtualization is not enabled" despite all virtualization features being fully enabled and confirmed working. CoworkVMService is running but the VM never starts.
Log output from cowork_vm_node.log:
2026-02-21 07:23:55 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 07:28:39 [warn] [startVM] VM not supported (win32/x64), skipping
Steps taken that did not resolve the issue:Verified CPU virtualization enabled in BIOS
Verified Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform all enabled in Windows Features
Ran Claude Desktop as Administrator
Full uninstall, deleted MSIX package data, clean reinstall
Rebooted multiple timesExpected behavior: Cowork should detect that hardware virtualization is fully enabled, download the VM bundle, and allow access to the Cowork workspace.
Actual behavior: yukonSilver VM configuration is marked as unsupported on a fully capable x64 Windows 11 Pro system, preventing the VM bundle from downloading and the Cowork tab from functioning.System Information
Operating System: Windows 11 Pro x64
CPU: Intel Core(TM) i7-10870H @ 2.20GHz (8 cores, 16 threads)
RAM: 64 GB
Claude Desktop Version: Latest (downloaded February 21, 2026 from claude.com/download)
Subscription: Claude ProSteps Taken and Verification
I have systematically enabled and verified all virtualization prerequisites:- Windows Features Enabled
All three required features have been enabled via optionalfeatures (Turn Windows features on or off):
• Hyper-V (including Hyper-V Platform and Hyper-V Management Tools) — Enabled ✅
• Virtual Machine Platform (Платформа виртуальной машины) — Enabled ✅
• Windows Hypervisor Platform — Enabled ✅
System was restarted after enabling these features.
2. BIOS/UEFI Hardware Virtualization
Intel VT-x is enabled in BIOS. Confirmed via Windows Task Manager → Performance → CPU, which displays "Виртуализация: Включено" (Virtualization: Enabled).
3. PowerShell Verification
Running the following command in Admin PowerShell:
Get-ComputerInfo | Select-Object HyperVisorPresent, HyperVRequirementVMMonitorModeExtensions, HyperVRequirementVirtualizationFirmwareEnabled
Result: HyperVisorPresent: True — confirming the hypervisor is active at the OS level.
4. Clean Reinstall of Claude Desktop
Performed a complete clean reinstall: uninstalled the app, deleted %APPDATA%\Claude directory, and installed a fresh download from claude.com/download. The Cowork tab now appears, but still shows the virtualization error.
Log Evidence
The log file at %APPDATA%\Claude\logs\cowork_vm_node.log consistently shows the following errors:
[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[startVM] VM not supported (win32/x64), skipping
[Callbacks] Swift VM addon not available for callbacks
These errors have been present since the initial installation on February 10, 2026, and persist through today (February 21, 2026) across multiple reinstalls and system restarts.
Current State
• Cowork tab IS visible in the Claude Desktop app (after clean reinstall with virtualization features enabled)
• Cowork displays the error: "Virtualization is not enabled — Claude’s workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer’s BIOS/UEFI settings, then restart."
• The Chat and Code tabs work perfectly
• All virtualization prerequisites are confirmed enabled at hardware, OS, and software levelsDespite all virtualization features being correctly enabled, Cowork still shows "Virtualization is not enabled" and the VM is marked as unsupported. This appears to be a detection bug — the system meets all requirements but yukonSilver incorrectly classifies it as unsupported.
- Windows Features Enabled
Exact same issue
2026-02-21 10:45:05 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 10:58:58 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...Environment:
OS: Windows 11 Pro, Version 25H2, Build 26200.7840
CPU: Intel Core i7-1360P (13th Gen)
RAM: 16GB
Claude Desktop: latest version (reinstalled clean)Confirmed enabled:
Intel VT-x (BIOS): ✅
Hyper-V (Microsoft-Hyper-V): ✅ Enabled
Virtual Machine Platform: ✅ Enabled
Windows Sandbox (Containers-DisposableClientVM): ✅ Enabled
Virtualization shown as "Enabled" in Task ManagerLog from %APPDATA%\Claude\logs\cowork_vm_node.log:
[warn] [startVM] VM not supported (win32/x64), skipping
[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
Steps tried:Enabled all virtualization features via Windows Features
Ran bcdedit /set hypervisorlaunchtype auto
Full clean reinstall (deleted %APPDATA%\Claude and %LOCALAPPDATA%\Claude, restarted, fresh install)
sc query CoworkVMService returns nothing — service was never createdResult: Cowork tab shows "Virtualization is not enabled" despite all prerequisites being met. The root cause appears to be the yukonSilver not supported (status=unsupported) detection incorrectly flagging Windows 11 Pro x64 as unsupported.
Reacted by antx0o02026-02-21 21:56:50 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
same issue... Please helpExact same issue #25136 (comment)
Please help
Device: HP Envy x360 (win32/x64)
OS: Windows 11 Pro (upgraded from Home specifically to meet Hyper-V requirements)
Claude Desktop version: latestProblem:
Cowork fails to start despite all virtualization requirements being met. The logs showyukonSilver not supported (status=unsupported)andVM not supported (win32/x64), skippingrepeatedly.Verified working:
- VT enabled in BIOS ✅
- Hyper-V enabled in Windows (State: Enabled) ✅
- Hypervisor active —
systeminfoshows "A hypervisor has been detected" ✅
Log output (
cowork_vm_node.log):[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle... [startVM] VM not supported (win32/x64), skippingThis appears to be the same root cause described in #25136. The hardware detection logic is incorrectly marking a fully capable machine as unsupported. Upgrading to Windows Pro did not resolve the issue.
Reacted by antx0o0Still broken on v1.1.3963 (Feb 22, 2026)
Windows 11 Pro Build 26100.7840, Hyper-V enabled, Pro plan, Canada
Same error after 5 updates: yukonSilver unsupported, VM not supported (win32/x64)
Tested versions: 2685 → 3363 → 3541 → 3963, all fail identicallyI had to completely uninstall and re-install (and probably reboot then) - 1.1.3963 does work now.
I had to completely uninstall and re-install (and probably reboot then) - 1.1.3963 does work now.
Thanks, complete uninstall and re-install worked!
1.1.4328 with Windows 11 pro Insider Preview Build 26200. Doesn't work.
Who can help? Many thanks!### Same issue here — Build 26200, yukonSilver marked unsupported
Environment:
Windows 11 Pro 25H2 (OS Build 26200.7840)
x64, Hyper-V enabled and running
Claude Desktop latest (reinstalled fresh)
Max plan subscriber
CoworkVMService is present and runningSymptoms:
Cowork tab does not appear — only Chat and Code visible
systeminfo reports: "A hypervisor has been detected. Features required for Hyper-V will not be displayed"
This is a physical machine (not a VM)Log output
(%APPDATA%\Claude\logs\cowork_vm_node.log):
[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[warn] [startVM] VM not supported (win32/x64), skipping
[error] [Callbacks] Swift VM addon not available for callbacks
This pattern repeats on every app launch since Feb 23. The VM never attempts to boot — the platform check rejects it before initialization.
Reinstalling the app does not resolve the issue. Awaiting a fix in the platform detection logic for Build 26200.Reacted by Robson Carvallho, tmartin-covetrus and EryetChenBeen going around in circles - the response I got from doing some testing and diagnosing
"The log confirms exactly what we suspected. The key lines are:
yukonSilver not supported (status=unsupported)
VM not supported (win32/x64), skipping
Swift VM addon not available for callbacks
This is Anthropic's bug, not yours. Claude Desktop is incorrectly classifying your perfectly capable Windows 11 Pro x64 system as unsupported. Your hardware is fine — it's a flaw in Cowork's platform detection logic.
This is a known bug reported by many others with identical setups to yours. There's nothing more you can do on your end to fix it — no settings to change, no workarounds that reliably solve it.
What I'd recommend now:Report it directly to Anthropic at support.claude.ai — include the fact that your log shows yukonSilver not supported (status=unsupported) on Windows 11 Pro x64 with a paid plan. The more people who report it, the higher priority it gets.
File or upvote the GitHub issue at github.com/anthropics/claude-code/issues/25136 — that's the exact bug affecting you. Adding a comment with your specs (Windows 11 Pro 64-bit, non-ARM) helps Anthropic see the scale of the problem.
Keep Claude Desktop updated — Anthropic are actively pushing fixes, and this detection bug is on their radar.I'm sorry it's not a more satisfying answer, Peter — you've done everything right and the problem is squarely on Anthropic's side."
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 12, 2026
Preflight Checklist
What's Wrong?
[BUG] Cowork tab not showing on Windows 11 Pro x64 — "yukonSilver" marked as unsupported + CoworkVMService cannot be removed
Preflight Checklist
What's Wrong?
After installing the latest Claude Desktop for Windows (v1.1.2685.0, downloaded Feb 11, 2026), the Cowork tab does not appear at all. Only "Chat" is available. The root cause appears to be two interrelated issues:
yukonSilverVM configuration is marked as "unsupported" — preventing the VM bundle from being downloaded and the Cowork tab from appearing.CoworkVMServicecannot be removed — the installer detects it as a "conflicting service" but fails to remove it with "Access is denied", even when running as Administrator.Environment
Symptoms
vm_bundlesfolder under%APPDATA%\Claudeis never createdLog Evidence
cowork_vm_node.log
This appears to be the primary issue: the VM configuration
yukonSilveris incorrectly classified as "unsupported" on a fully capable x64 Windows 11 Pro system with all virtualization features enabled.ClaudeSetup.log (repeated across multiple installation attempts)
The installer successfully installs the MSIX package (
INSTALL_SUCCESS), but:CoworkVMService(Access denied even with full elevation)explorer.exe claude://which fails because the protocol handler is not registeredManual removal also fails
The service cannot be removed even via Administrator PowerShell or registry manipulation.
Additional Installation Issue
The installer has a user account elevation conflict: When run by a non-admin user (e.g., "Fritz") and elevated to a different admin account (e.g., "Admin"), the MSIX is downloaded and installed in the Admin user's context (
C:\Users\Admin\AppData\Local\Temp\), making it invisible to the original user. The app does not appear in the non-admin user's Start menu.Workaround found: Running
Add-AppxPackagemanually as the target user installs the MSIX correctly for that user.Steps to Reproduce
%APPDATA%\Claude\logs\cowork_vm_node.logfor "yukonSilver not supported"%LOCALAPPDATA%\Temp\ClaudeSetup.logfor CoworkVMService access denied warningsExpected Behavior
yukonSilvershould be recognized as supported on this configurationSuggested Fixes
yukonSilverplatform detection logic — x64 Windows 11 Pro with Hyper-V should not be classified as "unsupported"claude://protocol handler during MSIX installation so the post-install launch worksWhat Should Happen?
Claude should be installed completely and correctly
Error Messages/Logs
See above (sorry, I'm first time hereSteps to Reproduce
Steps to Reproduce
Install Claude Desktop from claude.ai/download on Windows 11 Pro x64 (Build 26200)
Ensure all virtualization features are enabled (Hyper-V, VMP, WHP, WSL2)
Launch Claude Desktop
Observe: Only "Chat" tab visible, no "Cowork" tab
Check %APPDATA%\Claude\logs\cowork_vm_node.log for "yukonSilver not supported"
Check %LOCALAPPDATA%\Temp\ClaudeSetup.log for CoworkVMService access denied warnings
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
No response
Claude Code Version
1.1.2685
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
PowerShell
Additional Information
No response