How to fix fatal: invalid sha1 pointer in cache-tree in Git

First, run a full filesystem check to understand the extent of the corruption:

git fsck --full

This will show all corrupted objects. If you only see "invalid sha1 pointer in cache-tree" errors (not broken links or missing objects), the fix is straightforward.

Look for output like:

error: d193ccbc48a30e8961e9a2515a708e228d5ea16d: invalid sha1 pointer in cache-tree

This specifically indicates cache-tree corruption in the index file.

Before making any changes, backup your .git directory and any uncommitted work:

# Backup the entire .git directory
cp -r .git .git-backup

# If you have uncommitted changes, save them
git stash 2>/dev/null || true

Also note any staged changes you have that you want to preserve:

git diff --cached > staged-changes.patch 2>/dev/null || true

The cache-tree is stored in the .git/index file. Removing this file and resetting will regenerate it:

rm .git/index
git reset

The git reset command rebuilds the index from your current HEAD commit. Your working directory files remain unchanged—only the staging area is reset.

After running these commands, any previously staged changes will be unstaged, but your files themselves are untouched.

Run git fsck again to confirm the corruption is resolved:

git fsck --full

You should no longer see the "invalid sha1 pointer in cache-tree" error.

Then check that normal operations work:

git status
git log --oneline -5

If everything looks good, you can remove the backup:

rm -rf .git-backup

If you had staged changes before the corruption, you'll need to re-stage them:

# If you saved a patch earlier
git apply staged-changes.patch

# Or manually re-add your changes
git add -A

# Check what will be committed
git status

If you used git stash earlier, recover those changes:

git stash pop

If the simple index reset doesn't fix the issue and you have a remote repository, you can rebuild local objects from the remote:

# Remove local objects and re-fetch
rm -rf .git/objects/?? .git/objects/pack/*
git fetch --all

# Then reset the index
rm .git/index
git reset

Warning: This removes all local-only commits. Make sure your important commits are pushed to the remote first.

If the corruption is extensive and you have a remote:

# Save any local changes
cd ..
mv my-repo my-repo-corrupted

# Fresh clone
git clone <remote-url> my-repo
cd my-repo

# Copy over any uncommitted changes from the corrupted repo
# (manually copy files, don't copy .git directory)

This gives you a completely fresh repository state while preserving your working files.