Critical: After update, app refuses to start claiming another instance is running (none visible in processes)
Status Closed — not planned
Maintainer reply None cached
Workaround ✓ Mentioned in description ↑
Activity 10 comments · opened Apr 1, 2026 · closed Jun 27, 2026
Summary
After updating Claude Code to a new version, the application refuses to start with a message indicating another instance is already running. However, no Claude Code process is visible in Task Manager or process list.
Steps to reproduce
- Have Claude Code running
- Update arrives / gets installed
- Close Claude Code
- Try to relaunch Claude Code
- App shows error that another instance is already running
- Check Task Manager — no Claude Code process exists
Workaround
The only workaround found so far is to manually search for and kill any hidden lock files or restart the machine entirely.
Expected behavior
- After update, the application should start cleanly
- If a stale lock exists from a previous instance, it should be detected and released automatically
- The app should not rely on a lock mechanism that can become orphaned
Likely cause
A lock file or named pipe/mutex from the previous version persists after the process exits (possibly related to orphaned Node.js/bash child processes from #41742 that hold handles). The new version detects the stale lock and refuses to start, even though the original process is gone.
Environment
- OS: Windows 11
- Claude Code: occurs during version upgrades
10 Comments
same issue here
Same issue here. Seems to happen most often when an update happens while a session is in progress. E.g. I step away for a bit and come back to find the program updated itself without my permission, but won't launch again until I log out or restart.
I'm surprised so few people have commented on this issue. Does it only affect a very small subset of users? Is it some artifact of having installed an earlier version?
The problem has gone away on my machineVon meinem/meiner Galaxy gesendet
-------- Ursprüngliche Nachricht --------Von: celliso1 @.> Datum: 06.05.26 16:46 (GMT+01:00) An: anthropics/claude-code @.> Cc: Peter Henrichs @.>, Comment @.> Betreff: Re: [anthropics/claude-code] Critical: After update, app refuses to start claiming another instance is running (none visible in processes) (Issue #41743) celliso1 left a comment (anthropics/claude-code#41743)
I'm surprised so few people have commented on this issue. Does it only affect a very small subset of users? Is it some artifact of having installed an earlier version?
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This is affecting me with version 1.8555.2.0
I too am affected. Version 1.8555.2.0
Fixed me on last update Von meinem/meiner Galaxy gesendet
-------- Ursprüngliche Nachricht --------Von: ChapinLittleboy @.> Datum: 26.05.26 13:43 (GMT+01:00) An: anthropics/claude-code @.> Cc: Peter Henrichs @.>, Comment @.> Betreff: Re: [anthropics/claude-code] Critical: After update, app refuses to start claiming another instance is running (none visible in processes) (Issue #41743) ChapinLittleboy left a comment (anthropics/claude-code#41743)
I too am affected. Version 1.8555.2.0
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Closing for now — inactive for too long. Please open a new issue if this is still relevant.
same issue
same issue this week