I don\'t want to rename a remote branch, as described in Rename master branch for both local and remote Git repositories.
How can I rename a local branch wh
Probably as mentioned by others, this will be a case mismatch in branch naming.
If you have such a situation, I can guess that you're on Windows which will also lead you to:
$ git branch -m CaseSensitive casesensitive
fatal: A branch named 'casesensitive' already exists.
Then you have to do an intermediate step:
$ git branch -m temporary
$ git branch -m casesensitive
Nothing more.