How to handle git gc fatal: bad object refs/remotes/origin/HEAD error?

Question

I randomly hit this today while trying to run Git garbage collect:

$ git gc
fatal: bad object refs/remotes/origin/HEAD
error: failed to run repack
         


        

Answer 1

When all other answers fail, just restart your computer.

I encountered OP's error and also had Permission denied on some .gitattribute file in unrelated directory (no matter if run by admin or not). This helped me.