After git init, I added and committed a few files, made some changes, added and committed. Set up the git daemon (running under Cygwin on WinXP) and cloned the repository once.
Now, I get this error with the cloned repository:
$ git status
error: bad index file sha1 signature
fatal: index file corrupt
Is there any way to fix this, other than getting a new copy of the repository?
If the problem is with the index as the staging area for commits (i.e. .git/index), you can simply remove the index (make a backup copy if you want), and then restore index to version in the last commit:
On OSX/Linux/Windows(With Git bash):
rm -f .git/index
git reset
On Windows (with CMD and not git bash):
del .git\index
git reset
(The reset command above is the same as git reset --mixed HEAD)
You can alternatively use lower level plumbing git read-tree instead of git reset.
If the problem is with index for packfile, you can recover it using git index-pack.
This sounds like a bad clone. You could try the following to get (possibly?) more information:
git fsck --full
None of the existing answers worked for me.
I was using worktrees, so there is no .git folder.
You'll need to go back to your main repo. Inside that, delete .git/worktrees/<name_of_tree>/index
Then run git reset as per other answers.
Cloning remote repo and replacing the .git folder from it to problematic local directory solved the issue.
A repo may seem corrupted if you mix different git versions.
Local repositories touched by new git versions aren't backwards-compatible with old git versions. New git repos look corrupted to old git versions (in my case git 2.28 broke repo for git 2.11).
Updating old git version may solve the problem.
I did a simple trick. I clone the repo to a new folder. Copied the .git folder from the new folder to repo's old folder, replacing .git there.
rm -f .git/index
git reset
More info at https://www.chris-shaw.com/blog/quick-fix-for-git-corrupt-index