I have a fork of a Git repo and my clone appears to have an issue with an old, no longer existant, branch. I keep seeing this message:

`error: refs/heads/t_1140 does not point to a valid object!`

I don't have any other messages and the repo works fine. There's no operation that stops me from working on other branches, pushing changes, pulling...etc.

I've looked around and there's less than clear instructions on how to get around this issue. I've tried to execute `git fsck --full` but I see no errors. Just a load on `dangling ...` messages.

I've also checked my `.git/config` and there's no references to this branch and have also checked `.git/refs/heads` and there's no reference to `t_1140`

Any idea how to get rid of this error?

p.s I've tried to clone my repo again and it seems like the error is my Github repo too. So, the only thing I can think of right now is to ditch my repo and fork again.