Cannot switch branch

[Schroedingers-Cat]

I installed git-media on Windows 10 and it works using a local folder for git media sync. However; I am unable to switch branches. Git complains about git-media synced files being not committed.

git checkout master -f
error: Entry 'path/to/git-media-synced-file.wav' not uptodate. Cannot merge.

However, git status says

On branch branchname
Your branch is up-to-date with 'origin/branchname'.
nothing to commit, working directory clean

I started using git-media on branchname. Should I have started using git-media on branch master? I also cannot merge branchname with any other branch. What can I do now to get git working again?