Windows Education 10.0.26200: Claude Desktop HRESULT 0x80073CF6 — CoworkVMService artifact prevents reinstallation

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?

Claude Desktop cannot be reinstalled on Windows Education 10.0.26200. Installation fails consistently with HRESULT 0x80073CF6 and 0x80073D28, preventing any reinstallation despite numerous troubleshooting attempts.

What Should Happen?

Claude Desktop should install successfully on Windows Education 10.0.26200 without HRESULT errors. The installation should complete fully with both Claude and Cowork components functional.

Error Messages/Logs

Claude Desktop cannot be reinstalled on Windows Education 10.0.26200. 

I previously had Claude Desktop installed and working on this system for weeks. I used it extensively with Claude Code and MCP server integrations (Obsidian vault, Zotero, command systems). 

Following troubleshooting advice, I uninstalled Claude Desktop. Since then, all reinstallation attempts fail with HRESULT 0x80073CF6 and 0x80073D28 errors.

System Information:
- Windows Edition: Education
- Windows Version: 10.0.26200
- Architecture: x64
- Developer Mode: Enabled
- Full Administrator privileges confirmed

Attempted installations:
1. GUI installer (Claude Setup.exe) — Failed with 0x80073CF6
2. PowerShell as Administrator: Add-AppxPackage — Failed with 0x80073D28
3. Group Policy modification ("Allow all trusted apps to install") — Still fails
4. Manual MSIX extraction — Failed
5. Windows Image repair — Fails (requires elevation beyond available)

Error indicates CoworkVMService artifact or MSIX package stuck in partially-registered state. Similar to issues #49917, #56949, #49655.

Steps to Reproduce

1. Install Claude Desktop on Windows Education 10.0.26200 and use it for weeks (including Claude Code and MCP integrations)
2. Uninstall via Settings > Apps & Features
3. Clean AppData folders (C:\Users\Josh\AppData\Local\AnthropicClaude and Roaming\AnthropicClaude)
4. Attempt fresh reinstallation via Claude Setup.exe
5. Installation fails immediately with HRESULT 0x80073CF6 or 0x80073D28

Expected: Clean installation completes successfully
Actual: AddPackage fails; CoworkVMService artifact or MSIX package stuck in partially-registered state prevents reinstallation

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.7196 Claude code

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

<img width="1272" height="2772" alt="Image" src="https://github.com/user-attachments/assets/24679ddd-404c-4925-9dd0-e2cd64cc3939" />

=== ERROR 1: Initial Installation ===
Add-AppxPackage : Deployment failed with HRESULT 0x80073CF6, The package installation failed because administrator privileges are required. Please contact an administrator to install this package.
Claude_1.7196.3.0_x64__pzs8sxrjxfjjc: error 0x80073CF6: Cannot register the Claude_1.7196.3.0_x64__pzs8sxrjxfjjc package. Administrator privileges required to install packaged service.

=== ERROR 2: After Group Policy Change ===
Add-AppxPackage : Deployment failed with HRESULT 0x80073D28, The package installation failed because administrator privileges are required. Please contact an administrator to install this package.
Claude_1.7196.3.0_x64__pzs8sxrjxfjjc: error 0x80073D28: Cannot register the Claude_1.7196.3.0_x64__pzs8sxrjxfjjc package. Administrator privileges required to install packaged service

=== ERROR 3: Manual Extraction Attempt ===
Expand-Archive : .msix is not a supported archive file format. .zip is the only supported archive file format.

=== ERROR 4: 7-Zip Not Found ===
7z.exe : CommandNotFoundError
The term 'C:\Program Files\7-Zip\7z.exe' is not recognized

=== ERROR 5: Registry Repair Attempt ===
Repair-WindowsImage : The requested operation requires elevation.

=== All Attempts Show ===
Category: ObjectNotFound / FullyQualifiedErrorId: DeploymentError, Microsoft.Windows.Appx.PackageManager.Commands.AddAppxPackageCommand