Claude Desktop: Stale file lock after in-app update requires reboot (Windows)

Environment

• OS: Windows 11 Pro Build 26200
• App: Claude Desktop (Windows Store / WindowsApps install)
• Version attempting: 1.1062.0.0
• Shell: PowerShell 7.6.0

Bug

After clicking "Restart for update" in Claude Desktop, the app fails to relaunch with:

"Another program is currently using this file."

No Claude or Anthropic processes are running — confirmed via:

taskkill /f /im "Claude.exe"           # no matching processes
taskkill /f /im "Update.exe"           # no matching processes
Get-Process | Where-Object { $_.Path -like "*Claude*" -or $_.Path -like "*Anthropic*" }  # returns nothing

The file lock is stale — held at the OS/filesystem level with no owning process. The only resolution is a full Windows reboot.

Reproduction

1. Open Claude Desktop on Windows
2. When an update is available, click "Restart for update"
3. App closes but fails to relaunch with the file-in-use error
4. Verify no Claude/Anthropic processes exist (see commands above)
5. Attempting to launch manually also fails with the same error
6. Only a full Windows reboot resolves the lock

Frequency: 100% reproducible — occurred on the last 4 consecutive updates.

Expected Behavior

Clicking "Restart for update" should close the app, apply the update, and relaunch without requiring a system reboot.

Likely Cause

The updater process (Electron/Squirrel-based) is not fully releasing its file handle on the .exe or .asar before exiting. The OS retains the lock because the handle was not explicitly closed before process termination. Since the process no longer exists, there is no way to release the lock short of a reboot.

Workaround

Reboot Windows after every update.