Unable to git add/commit

[sieman216485]

Existing issues matching what you're seeing

• I was not able to find an open or closed issue matching what I'm seeing

Git for Windows version

git version 2.55.0.windows.3
cpu: x86_64
built from commit: 52ca1113d651127f89477a8763f86ab20f645e1d
sizeof-long: 4
sizeof-size_t: 8
shell-path: D:/git-sdk-64/usr/bin/sh
rust: disabled
feature: fsmonitor--daemon
gettext: enabled
libcurl: 8.21.0
OpenSSL: OpenSSL 3.5.7 9 Jun 2026
zlib: 1.3.2
SHA-1: SHA1_DC
SHA-256: SHA256_BLK
default-ref-format: files
default-hash: sha1

Windows version

Windows 11

Windows CPU architecture

x86_64 (64-bit)

Additional Windows version information

Microsoft Windows [Version 10.0.26200.8875]

Options set during installation

Editor Option: VIM
Custom Editor Path: 
Default Branch Option:  
Path Option: Cmd
SSH Option: OpenSSH
Tortoise Option: false
CURL Option: WinSSL
CRLF Option: CRLFAlways
Bash Terminal Option: MinTTY
Git Pull Behavior Option: Merge
Use Credential Manager: Enabled
Performance Tweaks FSCache: Enabled
Enable Symlinks: Disabled
Enable FSMonitor: Disabled

Other interesting things

No response

Terminal/shell

CMD

Commands that trigger the issue

> git add readme.txt

Expected behaviour

I expect the readme.txt file to be added for committing.

Actual behaviour

The above git add command failed with the following error message.

fatal: unable to write new index file

Repository

No response

[dscho]

fatal: unable to write new index file

This might be due to a couple of conditions, the following come to mind:

• You're trying this in a read-only directory
• The disk is full
• Anti-malware is temporarily holding an open file descriptor, preventing the file to be written
• A separate program is holding a lock (e.g. running git status in a tight loop)

Hopefully this helps identify the cause?

[sieman216485]

Hello @dscho, thanks for your reply. I've already checked your points.

I made sure the directory is definitely not read-only and that the disk has more than 100GB of free space. After disabling Windows Defender, the issue still occurs.

I also agree with your 4th point, since after trying many times, it only succeeded once.

I'm going to check if a separate program is holding a lock. Thanks again.