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Claude Code Issues / #28238

[BUG] Cowork tab shows "requires a newer installation" on Windows 11 Build 26200 — yukonSilver marked unsupported

Resolved 💬 16 comments Opened Feb 24, 2026 by anxhela-code Closed Apr 26, 2026

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?

The Cowork tab in Claude Desktop shows "Cowork requires a newer installation" and clicking the Reinstall button does nothing.

The cowork_vm_node.log consistently shows:

yukonSilver not supported (status=unsupported), checking for stale bundle...
[startVM] VM not supported (win32/x64), skipping
[Callbacks] Swift VM addon not available for callbacks

This persists after:

  • Enabling Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform
  • - Reinstalling Claude Desktop via winget (--force)
  • - - Downloading and reinstalling ClaudeSetup.exe from claude.com/download
  • - - - Rebooting after enabling virtualization features

The VM compatibility check rejects Windows 11 Build 26200 as unsupported. This is similar to #25136 which was reportedly fixed in v1.1.2998, but the issue persists on v1.1.4088.

What Should Happen?

The Cowork tab should load and be functional. The yukonSilver VM should recognize Windows 11 Pro Build 26200 (25H2) as a supported platform, since Hyper-V and all required virtualization features are enabled.

Error Messages/Logs

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

2026-02-24 11:21:17 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-24 10:31:57 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-24 10:31:57 [info] [Callbacks] Initializing VM event callbacks...
2026-02-24 10:31:57 [error] [Callbacks] Swift VM addon not available for callbacks

This pattern repeats on every launch since 2026-02-23. The VM is never started.

Steps to Reproduce

  1. Install Claude Desktop v1.1.4088 on Windows 11 Pro 25H2 (Build 26200.7840) via winget or ClaudeSetup.exe
  2. Enable Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform in Windows Features
  3. Reboot
  4. Open Claude Desktop
  5. Click the "Cowork" tab
  6. See "Cowork requires a newer installation" message
  7. Click "Reinstall" button — nothing happens
  8. Check %APPDATA%\Claude\logs\cowork_vm_node.log — shows yukonSilver unsupported

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop 1.1.4088 / Claude Code 2.1.50

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

  • OS: Windows 11 Pro 25H2 (Build 26200.7840)
  • - Plan: Pro
  • - - Hyper-V: Enabled (all sub-features)
  • - - - Virtual Machine Platform: Enabled
  • - - - - Windows Hypervisor Platform: Enabled
  • - - - - - Virtualization Enabled In Firmware: Yes
  • - - - - - - VM Monitor Mode Extensions: Yes
  • - - - - - - - Installed via winget (Anthropic.Claude) and also tried ClaudeSetup.exe from claude.com/download
  • - - - - - - - - Similar to #25136 which was closed as fixed in v1.1.2998, but the issue persists on v1.1.4088
  • - - - - - - - - - The "Reinstall" button in the Cowork tab triggers an "Application not found" error (broken URL handler on Windows)

View original on GitHub ↗

16 Comments

github-actions[bot] · 4 months ago

Found 3 possible duplicate issues:

  1. https://github.com/anthropics/claude-code/issues/28227
  2. https://github.com/anthropics/claude-code/issues/28219
  3. https://github.com/anthropics/claude-code/issues/27188

This issue will be automatically closed as a duplicate in 3 days.

  • If your issue is a duplicate, please close it and 👍 the existing issue instead
  • To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

dkinga · 4 months ago

Experiencing the same issue after upgrade that resolved Claude Desktop crash on startup (https://github.com/anthropics/claude-code/issues/28304).

Environment:

  • Claude Desktop: Version 1.1.4328
  • Windows 10 Pro 22H2, Build 19045.6466
  • Vivobook_ASUSLaptop X7400PC_N7400PC
  • CPU - 11th Gen Intel(R) Core(TM) i7-11370H @ 3.30GHz
  • 16GB, x64-based processor
  • Pro plan

Error message (%APPDATA%\Claude\logs\cowork_vm_node.log)
2026-02-25 19:09:01 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

pfaisant · 4 months ago

still getting same issue

realElShamy · 4 months ago

same at my end

anxhela-code · 4 months ago

Update (March 3, 2026):

Reinstalled Claude Desktop — now on v1.1.4498 (24f768), issue persists
Verified all 7 Hyper-V sub-features individually enabled via Get-WindowsOptionalFeature:
Microsoft-Hyper-V-All, Microsoft-Hyper-V, Microsoft-Hyper-V-Tools-All, Microsoft-Hyper-V-Management-PowerShell, Microsoft-Hyper-V-Hypervisor, Microsoft-Hyper-V-Services, Microsoft-Hyper-V-Management-Clients — all Enabled
The "Reinstall" button from the Cowork tab did not resolve anything
The fix suggested in similar issues (enabling Hyper-V via Enable-WindowsOptionalFeature) does not apply — everything was already enabled

dnitty67 · 4 months ago

same issue here, as well.

blakewylie · 4 months ago

Multiple users with the same issue here.

blakewylie · 4 months ago

Is there resolution to this yet? None of my Windows 11 users can use Claude CoWork. Thank you!

anxhela-code · 4 months ago

there has been no solution so far. I have Claude downloaded for my work office as well and no one can use CoWork. Need help ASAP

tiemenrtuinstra · 4 months ago

bug also persists on my end.

therealFlauwy · 3 months ago

Still affected on v1.1.7714.0 as of March 22, 2026 — fresh MSIX install, never had a Squirrel-based installation.

Environment:

  • Claude Desktop: v1.1.7714.0 (Claude_1.1.7714.0_x64__pzs8sxrjxfjjc)
  • OS: Windows 11 Pro
  • Subscription: Pro
  • Virtual Machine Platform: Enabled (verified via Get-WindowsOptionalFeature)
  • CoworkVMService: Running (verified via Get-Service)
  • Installed as Administrator from claude.ai/download

Steps taken:

  • No prior Claude Desktop installation existed
  • Downloaded fresh from claude.ai/download
  • Ran installer as Administrator
  • Verified MSIX package via Get-AppxPackage
  • Verified VirtualMachinePlatform Enabled
  • Verified CoworkVMService Running

Symptom:
Cowork tab shows 'Requires a newer installation' banner. Reinstall button does nothing. This is NOT an upgrade from a Squirrel-based package — it is a completely fresh install on a clean system.

Log from %APPDATA%\Claude\logs\cowork_vm_node.log:
2026-03-22 01:13:23 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-03-22 01:37:43 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

This confirms the bug is not limited to Squirrel upgrade paths and is still present in the latest build.

lbldproduction · 3 months ago

Still affected March 24th, 2026 on Claude v1.1.8359

Environment:

Claude Desktop: fresh install (March 24, 2026) - Claude 1.1.8359 (64248d) 2026-03-23T22:17:05.000Z
Windows 11 Pro (build: 26200.7840 )
Subscription: Pro

Issue:
Experiencing the same "Cowork requires a newer installation" banner on a completely fresh install — not an upgrade from a pre-Feb 10 Squirrel-based installation. The Reinstall button in the UI does nothing.

Log from %APPDATA%\Claude\logs\cowork_vm_node.log:
[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)

Troubleshooting already completed:
Fresh install from claude.com/download (not an upgrade)
Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform all enabled
Developer Mode enabled in Windows settings
Full uninstall including clearing %APPDATA%\Claude and %LOCALAPPDATA%\Claude before reinstalling
Intel Virtualization (VT-x) confirmed enabled in BIOS

ghost · 3 months ago

Fix: Cowork Tab Greyed Out / "Requires Newer Installation" on Windows (Domain Environments)

Problem

After installing Claude Desktop on Windows, the Cowork tab is greyed out and shows a message like "Cowork requires a newer installation". Clicking the "Reinstall" button does nothing, and "Check for Updates" falsely reports the latest version is installed.

This is especially common in domain/enterprise environments where the logged-in user is not a local admin and installation requires elevation to a separate admin account.

Root Cause

There are two issues at play:

  1. Squirrel vs. MSIX packaging: Older Claude Desktop installations (or fresh installs that don't get the MSIX package) use the legacy Squirrel installer, which does not support Cowork. Cowork requires the newer MSIX package format.
  1. Admin elevation installs to wrong user context: In domain environments, when a non-admin user runs the installer and elevates to a different admin account via UAC, the MSIX package gets installed in the admin's user context — making it invisible to the actual user. The user ends up running the old Squirrel version without realizing it.

Environment

  • Windows 11 Pro (domain-joined)
  • User does not have local admin rights
  • Separate admin account used for software installation
  • Claude Desktop downloaded from claude.ai/download

Solution

Step 1: Enable Virtualization Features

Cowork runs inside a Hyper-V virtual machine. All virtualization features must be enabled.

Run in Admin PowerShell:

# Check current state
Get-WindowsOptionalFeature -Online | Where-Object { $_.FeatureName -match "Hyper-V|VirtualMachinePlatform|HypervisorPlatform" } | Select FeatureName, State

# Enable all required features
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All, VirtualMachinePlatform, HypervisorPlatform -All -NoRestart

Reboot the PC after enabling these features.

After reboot, verify in Admin PowerShell that all features show Enabled:

Get-WindowsOptionalFeature -Online | Where-Object { $_.FeatureName -match "Hyper-V|VirtualMachinePlatform|HypervisorPlatform" } | Select FeatureName, State

Step 2: Clean Up Old Installation

Run as the affected user (normal PowerShell, not Admin):

# Stop Claude if running
Stop-Process -Name "Claude" -Force -ErrorAction SilentlyContinue

# Remove old Squirrel installation
Remove-Item -Recurse -Force "$env:LOCALAPPDATA\AnthropicClaude" -ErrorAction SilentlyContinue

# Remove old config/cache
Remove-Item -Recurse -Force "$env:APPDATA\Claude" -ErrorAction SilentlyContinue

# Remove old updater
Remove-Item -Recurse -Force "$env:LOCALAPPDATA\claude-desktop-updater" -ErrorAction SilentlyContinue

Step 3: Run the Installer to Generate the MSIX File

Download the latest installer from claude.ai/download and run it normally (it will prompt for admin credentials). Let it complete — even though it may install to the wrong user context, it creates the .msix file we need.

Step 4: Install MSIX Package System-Wide via DISM

This is the key step that makes it work in domain environments.

Run in Admin PowerShell:

# Find the MSIX file (created by the installer in a Temp folder)
Get-ChildItem "C:\Users\*\AppData\Local\Temp\" -Filter "Claude*.msix" -Recurse -ErrorAction SilentlyContinue

Note the full path of the newest .msix file, then provision it system-wide:

# Replace the path below with the actual path from the previous command
DISM /Online /Add-ProvisionedAppxPackage /PackagePath:"C:\Users\USERNAME\AppData\Local\Temp\Claude-XXXXXXXXXX.msix" /SkipLicense

This registers the MSIX package for all users on the machine, bypassing the user-context problem.

Step 5: Verify and Launch

Run as the affected user (normal PowerShell, not Admin):

# Verify MSIX package is registered for your user
Get-AppxPackage -Name "*Claude*"

You should see output with Name: Claude, Status: Ok, and an InstallLocation under C:\Program Files\WindowsApps\.

If that looks good, also verify the VM service is running:

Get-Service -Name "CoworkVMService" -ErrorAction SilentlyContinue

Now launch Claude from the Start Menu (search for "Claude").

⚠️ Important: Make sure you're launching the new MSIX version, not the old Squirrel version. If you cleaned up Step 2 properly, only the correct version should remain. You can verify by checking which executable is running: ``powershell Get-Process -Name "Claude" -ErrorAction SilentlyContinue | Select-Object Path ` The path should be under C:\Program Files\WindowsApps\Claude_..., **not** under AppData\Local\AnthropicClaude\`.

If Claude doesn't appear in the Start Menu, launch it directly:

explorer.exe shell:AppsFolder\Claude_pzs8sxrjxfjjc!Claude

The Cowork tab should now be active and functional.

Troubleshooting

MSIX file not found in Step 4

If Get-ChildItem returns no results, the installer may not have run successfully. Try running the installer again as admin and check immediately after.

Get-AppxPackage returns nothing after DISM

The user may need to log out and back in for the provisioned package to register.

Cowork tab visible but shows "Cannot connect to Claude API"

This is a different issue — usually related to VM networking. Check if a VPN is interfering and try disabling it. See also: [Issue #24918](https://github.com/anthropics/claude-code/issues/24918)

CoworkVMService not running

In Admin PowerShell:

Start-Service -Name "CoworkVMService"

Summary

The core fix for domain environments is: don't rely on the installer to register the MSIX for the correct user. Instead, use DISM /Add-ProvisionedAppxPackage to provision it system-wide, then clean up any old Squirrel installation remnants so the user launches the correct version.

Related Issues

therealFlauwy · 3 months ago

The proposed fix from falk-code187 has worked for me and Claude Dispatch is now running.

github-actions[bot] · 2 months ago

Closing for now — inactive for too long. Please open a new issue if this is still relevant.

github-actions[bot] · 2 months ago

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.