claude-launch-fix

Recovers the Claude desktop app on Windows when it will not start after an auto-update and Windows reports "The process cannot access the file because it is being used by another process" (error 0x80070020). Settings > Apps > Repair does not help; signing out or rebooting does, but is not needed.

Cause (confirmed 2026-09-18)

A program started from a Claude Code session that detaches and keeps running after the app quits. In the confirmed case it was the Android adb server (adb.exe), started by an adb command Claude ran in the Code tab.

Commands run by Claude Code start inside the desktop app's sandbox (its Desktop AppX container). adb forks a background server that cuts its ties to the shell. When the auto-update quits the app, every Claude process exits but the adb server does not, so the old version's sandbox stays alive and keeps Claude's per-user package registry hive mounted (%LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\SystemAppData\Helium\*.dat). Windows then cannot create the sandbox for the new version, and every launch fails before any Claude code runs, which is why Claude's own main.log shows nothing.

Why it was hard to find:

• tasklist /apps does not list the adb server: it has no package identity.
• Its parent process is gone, so it does not look related to Claude.
• Sysinternals handle.exe finds no handle into the hive or the sandbox. Being a member of the sandbox is enough to keep it alive.

The proof, from Unblock-Claude.ps1 on 2026-09-18 (Claude 2.2553.1.0, Windows 11 26200):

03:48:56 Baseline hive: LOCKED
03:49:09   launch: 0 Claude proc, 6 new 0x80070020
03:49:09 --- 1 Gradle daemons
03:49:09   kill PID 18544
03:49:12   hive: LOCKED
03:49:25   launch: 0 Claude proc, 6 new 0x80070020
03:49:25 --- 2 adb
03:49:29   hive: free
03:49:42   launch: 11 Claude proc, 0 new 0x80070020
03:49:42 RESULT: FIXED BY adb kill

Killing the Gradle daemon (also started from the Code tab) did not release the hive on its own; stopping adb did, within seconds. Any other detached long-lived program started from a Claude Code session (dev servers, emulators, file watchers) is a suspect for the same reason.

Evidence in Event Viewer: Applications and Services Logs > Microsoft > Windows > AppModel-Runtime > Admin, events 215 and 208 with 0x80070020 ("error converting the job").

Reported as anthropics/claude-code#95266.

The quick fix

adb kill-server

then start Claude. If adb is not on the PATH, end adb.exe in Task Manager.

To avoid it: run adb kill-server when you are done with a device or emulator in a Claude Code session, before the app next updates.

Use the script

1. Get the files onto the PC (see below).
2. Double-click Fix-ClaudeLaunch.cmd. It
   • lists the processes running as part of Claude and flags any from an older version,
   • finds leftovers of Claude Code sessions that carry no package identity,
   • if nothing of Claude is left but its hive is still locked, offers to stop the adb server and Gradle daemons one at a time, checking the hive after each, so the log names the process that was responsible,
   • asks before stopping anything, relaunches Claude and reports whether the error came back.
3. Still blocked? Stop anything else you started from a Claude Code session, or sign out of Windows and back in. No full reboot needed.

Run it as administrator if the normal run finds nothing.

Fix-ClaudeLaunch.log (written next to the script, not committed) records what was stopped and which step released the hive; worth attaching to a bug report.

Report only, changes nothing:

powershell -NoProfile -ExecutionPolicy Bypass -File Fix-ClaudeLaunch.ps1 -DryRun

If Claude was installed from the .exe rather than the Store, the script instead offers to stop every leftover Claude desktop process and relaunches from %LOCALAPPDATA%\AnthropicClaude.

Unblock-Claude.ps1 is the experiment that found the cause, kept as it was run: elevated, no prompts, it kills Gradle daemons, then the adb server, then restarts the Appinfo service, relaunching Claude after each and stopping at the first step that works. Prefer Fix-ClaudeLaunch, which asks first.

Getting it onto another PC

git clone https://github.com/nimbice/claude-launch-fix.git C:\Scripts\claude-launch-fix

or open the repo on github.com and use Code > Download ZIP.

No download at all: the fix by hand

In PowerShell, as the normal user:

Get-Process adb -ErrorAction SilentlyContinue | Stop-Process -Force   # the confirmed culprit
explorer.exe shell:AppsFolder\Claude_pzs8sxrjxfjjc!Claude             # relaunch

If that was not it, look for an old-version process:

Get-AppxPackage Claude | Select-Object PackageFullName   # the version that should be running
tasklist /apps | findstr Claude_                          # what is actually running
taskkill /F /PID <pid>                                    # every row whose version is OLDER