[BUG] Windows update fails with 0x80073CF6 (AddPackage failed) — updater doesn't close app before installing

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?

When Claude detects an update and the user clicks to install, the update fails with:

Installation failed: AddPackage failed with HRESULT 0x80073CF6
Root cause: The updater downloads the new .msix to %LOCALAPPDATA%\Temp\Claude-*.msix and attempts to install it while Claude's processes are still running. Windows cannot replace an MSIX package with active processes from that package, causing error 0x80073CF6 (ERROR_PACKAGES_IN_USE).

Steps to reproduce:

Use Claude desktop app on Windows until an update notification appears
Click the update notification / accept the update prompt
Error dialog appears: "Installation failed: AddPackage failed with HRESULT 0x80073CF6"
Expected behavior: The updater should call Add-AppxPackage -ForceApplicationShutdown (or equivalent) to terminate running instances before installing the new package.

Workaround: Manually kill all claude.exe processes and run Add-AppxPackage -Path <downloaded.msix> -ForceApplicationShutdown from an elevated PowerShell prompt.

Environment:

OS: Windows 11 Pro 10.0.26200
Claude version: 1.15200.0.0
Install method: MSIX package (Claude_pzs8sxrjxfjjc)

Related: #63518 (different root cause — that issue was about fresh installs; this is about the updater not closing running instances before reinstalling)

What Should Happen?

The updater should close all running Claude processes before attempting to install the new MSIX package (e.g. using Add-AppxPackage -ForceApplicationShutdown), so the update completes without user intervention.

Error Messages/Logs

Steps to Reproduce

Steps to reproduce:

Use Claude desktop app on Windows until an update notification appears
Click the update notification / accept the update prompt
Error dialog appears: "Installation failed: AddPackage failed with HRESULT 0x80073CF6"
Expected behavior: The updater should call Add-AppxPackage -ForceApplicationShutdown (or equivalent) to terminate running instances before installing the new package.

Workaround: Manually kill all claude.exe processes and run Add-AppxPackage -Path <downloaded.msix> -ForceApplicationShutdown from an elevated PowerShell prompt.

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_