[BUG] Claude Desktop MSIX fails to launch on Windows 11 — EBADF on renameSync in git-worktrees.json

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 (MSIX version 1.1.9310.0) fails to launch with error "Claude Desktop failed to Launch". The app crashes before any window is created due to an EBADF error on renameSync when writing git-worktrees.json. PackageUserInformation remains empty {} after installation, indicating the MSIX package is not properly registered to the user.

What Should Happen?

Claude Desktop should launch successfully after MSIX installation.

Error Messages/Logs

Error: EBADF: bad file descriptor, rename 'C:\Users\29638\AppData\Roaming\Claude\git-worktrees.json.tmp-4716226946741ed5' -> 'C:\Users\29638\AppData\Roaming\Claude\git-worktrees.json'
    at renameSync (node:fs:1018:11)
    at a (...\app.asar\.vite\build\index.js:94:15143)
    at Object.u [as writeFileSync] (...\app.asar\.vite\build\index.js:94:22227)
    at c._write (...\app.asar\.vite\build\index.js:102:41842)
  errno: -4083, code: 'EBADF', syscall: 'rename'

main.log is always empty — app crashes before writing any log.
CoworkVMService starts normally (HCS DLLs loaded, named pipe listening).
PackageUserInformation: {} (empty after every install attempt)

Steps to Reproduce

1. Download Claude Desktop from claude.ai/download (Windows x64)
2. Run Claude Setup.exe — installation completes successfully
3. Launch Claude Desktop
4. Error dialog appears: "Claude Desktop failed to Launch"
5. Verify with: Get-AppxPackage -Name "Claude" | Select-Object Name, Version, Status, PackageUserInformation — PackageUserInformation is {}
6. Launch exe directly to get error: Start-Process "C:\Program Files\WindowsApps\Claude_1.1.9310.0_x64__pzs8sxrjxfjjc\app\claude.exe" — outputs EBADF renameSync error

Attempted fixes (all failed): complete uninstall+cleanup+reboot+reinstall, Add-AppxPackage re-register, pre-creating git-worktrees.json in both real and MSIX VFS paths, disabling antivirus (Huorong), launching via shell:AppsFolder.

Workaround: winget install Anthropic.Claude (installs Squirrel version 1.1.9134, Chat/Code/Dispatch work but Cowork unavailable)

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

N/A — this is a Claude Desktop issue

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

System: Windows 11 Pro 25H2 (Build 26200), Intel i7-14650HX, 32GB RAM
Virtualization: Enabled, Developer Mode: Enabled

!Image

Related issues: #25914, #40067, #25385