### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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? Since updating from 1.44121.4 to 1.46388.1, no new Code session can be created on Windows. The UI shows a misleading error: "Impossible de changer de bran

[BUG] Claude Desktop 1.46388.1 (Windows): session worktree creation fails — checkout.workers=7 vs core.fscache

Status Open

Reported on v2.1.260

Maintainer reply None cached

Workaround ✓ Mentioned in description ↑

Activity 0 comments · opened Sep 4, 2026

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?

Since updating from 1.44121.4 to 1.46388.1, no new Code session can be created on Windows. The UI shows a misleading error: "Impossible de changer de branche. Effectuez un commit ou remisez vos modifications..." while the repository is completely clean.

What Should Happen?

was working before without problem

Error Messages/Logs

2026-09-04 08:48:10 [info] Created worktree "..." (last success, on 1.44121.4)
2026-09-04 09:05:49 [info] [updater] Version changed since last launch: 1.44121.4 -> 1.46388.1
2026-09-04 14:35:43 [error] Git command failed: git -c core.longpaths=true -c checkout.workers=7 checkout HEAD -- . :(exclude).claude
                            stderr: "warning: unable to unlink '.agents': Directory not empty
                                     fatal: cannot create directory at '.agents': Directory not empty"
2026-09-04 14:40:44 [error] Failed to remove worktree directory EBUSY: resource busy or locked, rmdir '...'

Steps to Reproduce

git init repo && cd repo
for d in adir bdir cdir; do mkdir -p $d/sub; for i in $(seq 1 60); do echo x > $d/sub/f$i.txt; done; done
git add -A && git commit -m init
git worktree add --no-checkout --detach wt
git -C wt -c checkout.workers=7 checkout HEAD -- . # fatal
git -C wt -c checkout.workers=7 -c core.fscache=false checkout HEAD -- . # OK
git -C wt -c checkout.workers=1 checkout HEAD -- . # OK

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Desktop 1.46388.1 (MSIX / Microsoft Store), CCD 2.1.260

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

Environment
Claude Desktop 1.46388.1 (MSIX / Microsoft Store), CCD 2.1.260
Windows 11 Enterprise 10.0.26200
git version 2.50.1.windows.1, core.fscache unset (Git for Windows default = true)
Worked on 1.44121.4 the same morning; first failure right after the auto-update.
Impact
Every new session fails. checkout.workers=7 is passed on the command line, so users cannot neutralize it via git config (-c outranks config files, and checkout.thresholdForParallelism has no effect either). The only user-side workaround is core.fscache=false, i.e. degrading git performance machine-wide to work around an app regression.
Each failure leaves an orphan directory in .claude/worktrees/ (worktree remove fails with Permission denied / EBUSY), so the folder keeps growing and the app logs "not safe to rm. Remove manually if no longer needed."

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