[BUG] Cowork toggle grayed out in Claude Desktop for Windows despite correctly installed MSIX package (v1.24012.9.0)

[meule7]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Note: This bug affects Claude Desktop for Windows (not Claude Code CLI).
Filing here because there is no separate Claude Desktop repository,
and similar issues (#69034, #28998) are also filed in this repo.

The Cowork toggle in Claude Desktop for Windows is permanently grayed out.
Hovering over it shows the tooltip: "Cowork erfordert, dass Claude Desktop
mit unserem modernen Installer installiert wird" ("Cowork requires Claude
Desktop to be installed with our modern installer").

This happens even though:

• The MSIX package is correctly installed and reported by
  Get-AppxPackage *claude* as Claude_1.24012.9.0_x64__pzs8sxrjxfjjc
• The Cowork settings page is fully accessible and shows all Cowork-related
  options (trusted folders, global instructions, artifact storage path, etc.)
• Only the actual Cowork toggle in the message composer is grayed out

Intermittent behavior (important): On one occasion, Cowork worked correctly
for a single session. The next day, without any system changes, the button
was grayed out again with the same tooltip. This strongly suggests the app
loses its "modern installer" state between sessions.

What Should Happen?

With a correctly installed current MSIX package (as confirmed by
Get-AppxPackage), the Cowork toggle in the message composer should be
clickable and Cowork sessions should be usable.

The current tooltip "modern installer required" is misleading because the
installation IS modern (MSIX format, latest version). The app appears to
have a stale internal state that incorrectly reports the installer as
outdated.

Error Messages/Logs

Tooltip shown on hover over the Cowork toggle (German UI):
"Cowork erfordert, dass Claude Desktop mit unserem modernen Installer installiert wird"

PowerShell output confirming a correctly installed MSIX package:

PS C:\Windows\system32> Get-AppxPackage *claude* | Select Name, PackageFullName, Version

Name    PackageFullName                            Version
----    ---------------                            -------
Claude  Claude_1.24012.9.0_x64__pzs8sxrjxfjjc      1.24012.9.0

Note: The package identity string ends in a publisher hash, confirming this
is an MSIX installation, not a legacy Squirrel installation. Despite this,
the app reports that a "modern installer" is required.

No error dialogs or crash logs are produced. The failure is silent — the
toggle is simply disabled.

Steps to Reproduce

1. Install Claude Desktop from claude.com/download as Administrator on Windows 11
2. Sign in with a paid plan account
3. Observe the Cowork toggle in the message composer → grayed out with tooltip about modern installer

<img width="555" height="194" alt="Image" src="https://github.com/user-attachments/assets/bc8a54fa-6418-4ae3-8714-1700a6d3ca35" /

Claude Model

None

Is this a regression?

I don't know

Last Working Version

Same version (1.24012.9.0) – worked once, then stopped

Claude Code Version

N/A – Claude Desktop 1.24012.9.0 (not Claude Code CLI)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

NOTE: This is a Claude Desktop bug, not Claude Code CLI. The form fields above
are Claude Code specific and filled with placeholders where not applicable.

Environment:

• OS: Windows 11
• CPU: Intel Core Ultra 5 125U
• RAM: 32 GB
• Claude Desktop version: 1.24012.9.0
• Package identity: Claude_1.24012.9.0_x64__pzs8sxrjxfjjc (MSIX)
• Corporate laptop with full local admin rights, no restrictive IT policies
• Virtualization enabled in BIOS (confirmed as "Aktiviert" in Task Manager)
• Windows features enabled: Virtual Machine Platform, Windows Hypervisor Platform

Troubleshooting already performed:

• Reinstalled multiple times via official installer from claude.com/download
  (Right-click → Run as Administrator, UAC confirmed)
• Removed installation via Get-AppxPackage claude | Remove-AppxPackage
• Deleted/renamed app data folder at %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc
• Multiple full restarts (real restart, not Fast Startup)
• Verified all virtualization prerequisites

Anthropic support suggested Add-AppxProvisionedPackage for machine-wide install,
but the installer at claude.com/download is a bootstrapper .exe, not a .msix file,
so end users cannot execute this command. Support recommended filing here.

Related: #69034, #28998

[Colellla09]

I am having the same issue. Has there been a fix for this? Anthropic support appears to be suggesting the same fix to uninstall and download the desktop app however this is not working.