One thing I’ve noticed: If even a single file in the repo exceeds 260 characters in its filename, the repo has errors.
Try installing the repo on the top level of your pc. For example:
c:\Github\FE Repo
And use a short name too, not Fire Emblem Graphics Repository, but just FE Repo. This keeps the filepath as short as possible.
In the future, I’ll be shortening tons of files and folders down to eliminate this issue.
If that doesn’t work, lmk. Other things can cause that error.