How to Fix “fatal: bad object” Error in Git

What is a “fatal: bad object” Error?

This Git error is serious. It indicates a problem with Git’s internal database. The .git/objects directory stores all your content. Content is stored in objects (commits, trees, blobs). The “bad object” error means an object is missing or corrupted. Git cannot read it. This can happen due to hardware failure. A disk error or power outage can corrupt files. It can also happen if the .git directory is improperly modified.

How to Diagnose the Problem

First, you need to check the repository’s integrity. Git has a built-in tool for this. The command is git fsck.

Step 1: Run git fsck

git fsck --full

This command checks the database for any corrupted or dangling objects. It will likely report the same “bad object” error. But it may also provide more details. It might list missing objects or other inconsistencies. Pay attention to the hash of the bad object.

How to Recover from the Error

Recovery depends on the situation. Do you have a clean remote copy of the repository? Or are you working on a local-only repository?

Scenario 1: You Have a Clean Remote Repository

This is the easiest scenario to fix. You can fetch the missing objects from the remote.

Step 1: Fetch from the remote

git fetch --all

This command downloads all missing objects from all your remotes.

Step 2: Check integrity again

git fsck --full

If the command now reports no errors, the problem is solved.

Step 3: If errors persist, try a fresh clone Sometimes, local corruption is too severe. The safest solution is to re-clone the repository. First, back up any un-pushed local changes. You can create a patch or simply copy the modified files elsewhere.

# 1. Back up your work (e.g., copy files to another folder)
# 2. Move the old, corrupted repository
mv my-corrupted-repo my-corrupted-repo-backup

# 3. Clone a fresh copy
git clone <your-remote-url>

# 4. Re-apply your changes to the new repository

Scenario 2: You Do Not Have a Remote Repository

This situation is much more difficult. The corrupted object is likely lost forever. You cannot easily recover the exact state of that commit.

Option 1: Remove the bad object (Last Resort)

This is a destructive action. It may lead to losing part of your project’s history. Only do this if you have no other choice.

# Find the path to the bad object using its hash
# Example hash: a1b2c3d4...
# Path: .git/objects/a1/b2c3d4...

# Remove the corrupted object file
rm .git/objects/a1/b2c3d4... 

After removing it, you will need to deal with the broken history. This might involve complex git rebase operations.

Option 2: Restore from a backup

If you have a backup of your local repository, now is the time to use it. Restoring from a backup is the safest way to recover.

How to Prevent This Error

• Regularly back up your repositories. This is critical for local-only projects.
• Use reliable hardware. Disk failures are a common cause of corruption.
• Avoid manually editing the .git directory. Unless you know exactly what you are doing.
• Push your changes often. A remote repository is the best backup.

Conclusion

The “fatal: bad object” error is a sign of repository corruption. The best solution is to restore from a remote or a backup. If you have no backup, recovery is difficult and may result in data loss. Regularly running git fsck can help you detect problems early. Proactive backups are the best defense against this error.