[BUG] Desktop app Update button does nothing; old install never gets replaced or unpinned

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?

The in-app Update button (shown when a banner says a newer model needs the latest desktop app) does not do anything when clicked. No download starts, no error appears, no new process launches. Confirmed this directly: watched running processes and file timestamps across multiple clicks, nothing changed.

The only thing that has ever actually updated the app is manually re-downloading and re-running the Setup.exe bootstrapper from scratch.

Found a second, related bug while diagnosing this. My machine had two completely separate installs:

1. An old Squirrel-based install at %LOCALAPPDATA%\AnthropicClaude\app-extracted\app\claude.exe, untouched for over a month.
2. A newer MSIX-based install (Claude_<packagefamily>, installed via the Claude Setup.exe bootstrapper) sitting unused in Program Files\WindowsApps.

The Start Menu shortcut and taskbar pin both still pointed at the old Squirrel exe. So every time I clicked the Claude icon I normally use, Windows launched the dead old build, never the new MSIX install, even after the new one was successfully installed. I only found this by manually inspecting shortcut targets and running processes.

ClaudeSetup.log (from a real reinstall) confirms the installer downloads and installs the new MSIX correctly, but explicitly logs "No Squirrel installation found, skipping uninstall" and never touches the old Start Menu/taskbar shortcuts, so they're left pointing at the dead build.

Net effect: a user can download the "latest" installer, have it succeed, and still keep running an ancient build indefinitely because (a) the shortcuts never get repointed, and (b) the in-app Update button that's supposed to catch this later does nothing.

Windows 10, desktop Claude app. Happy to provide more logs/output if useful.

What Should Happen?

Clicking Update should download and install the latest version, and any shortcuts (Start Menu, taskbar) left over from a prior install method should be repointed at the current install, not left pointing at a dead build.

Error Messages/Logs

Steps to Reproduce

1. Have an existing Squirrel-based install of the desktop app (older install method).
2. Download and run Claude Setup.exe, which installs a new MSIX-based version successfully.
3. Note that Start Menu/taskbar shortcuts still point at the old Squirrel exe, not the new MSIX app.
4. Launch Claude from those shortcuts, it opens the old dead build.
5. In the old build, click "Update" when prompted, nothing happens, no download, no error, no new process.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.278 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_