Git Worktree Lock Conflict — Fix (2026)

The Error

fatal: 'feature-auth' is a missing but locked worktree
  use 'git worktree unlock' to unlock it, or 'git worktree remove' to remove it
  lock reason: Claude Code session (PID 48291) — process no longer running

This appears when a previous Claude Code session created a git worktree and the session crashed without cleaning it up, leaving a stale lock.

The Fix

git worktree unlock feature-auth
git worktree prune
  1. Unlock the stale worktree.
  2. Prune all dead worktrees whose directories no longer exist.
  3. Verify the worktree list is clean: git worktree list.

Why This Happens

Claude Code’s worktree feature creates isolated git worktrees in .claude/worktrees/ for parallel development. Each worktree gets locked to prevent concurrent access. When Claude Code exits abnormally (crash, SIGKILL, OOM), it cannot release the lock. Subsequent sessions that try to use the same worktree name find it locked by a non-existent process.

If That Doesn’t Work

Force remove the problematic worktree:

git worktree remove --force feature-auth

If the worktree directory was already deleted:

git worktree prune --verbose

Manually clean up stale worktree references:

rm -rf .git/worktrees/feature-auth
rm -rf .claude/worktrees/feature-auth
git worktree prune

Prevention

# CLAUDE.md rule
After a Claude Code crash, always run 'git worktree prune' to clean up stale worktrees. Use 'git worktree list' to verify no orphaned worktrees exist before starting a new session.

See Also

This fix also applies if you see these related error messages:

  • fatal: not a git repository
  • error: failed to push some refs
  • fatal: refusing to merge unrelated histories
  • FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed
  • Killed (signal 9) — OOM killer

Frequently Asked Questions

Why does Claude Code require git?

Claude Code uses git for several core operations: tracking file changes, creating commits, reading blame information, searching history with git log, and managing branches. Without git, these operations fail and Claude Code falls back to less efficient alternatives.

Can Claude Code work in a non-git directory?

Yes, but with reduced functionality. File search and editing work normally, but version control operations (commit, diff, blame) are unavailable. Claude Code displays a warning when opened in a directory without git initialization.

How do I prevent Claude Code from making unwanted git operations?

Add rules to your CLAUDE.md: Do not create commits automatically. Do not run git push. Always ask before any git operation that modifies history. Claude Code respects these constraints and asks for confirmation before proceeding.

What triggers OOM in Claude Code?

Reading very large files (over 10MB), processing repositories with more than 100,000 files, or accumulating a long conversation history without starting a fresh session. Each of these increases memory consumption beyond the default Node.js heap limit.

Try it: Paste your error into our Error Diagnostic for an instant fix.

Git Operations in Claude Code: Safety Checklist

Claude Code can execute git commands, which makes safety guardrails important:

Before any destructive operation: Always check git status and git stash list to confirm there are no uncommitted changes that could be lost.

Branch management: Claude Code should create feature branches for non-trivial changes rather than committing directly to main. Use the pattern git checkout -b claude/feature-name to clearly identify AI-generated branches.

Commit message conventions: Configure your preferred commit format in CLAUDE.md. Claude Code follows the format you specify. Common formats: Conventional Commits (feat: add user search), Angular style, or simple descriptive messages.

Common Git Mistakes Claude Code Makes

  1. Amending the wrong commit. If a pre-commit hook fails, Claude Code sometimes uses --amend on the next attempt, which modifies the previous (successful) commit instead of creating a new one. Configure CLAUDE.md with: “Never use git commit –amend. Always create new commits.”

  2. Force pushing to shared branches. Claude Code may suggest git push --force to resolve push rejections. Add Bash(git push --force*) to your deny list in settings.json.

  3. Committing generated files. Without guidance, Claude Code may commit dist/, node_modules/, or .env files. Ensure your .gitignore is complete and add a pre-commit hook that checks for these.