I think you’ve got a “git repository” set up on your desktop. Maybe in an earlier version of PsychoPy you opened an experiment on your desktop and tried to sync it with Pavlovia (which will try to sync the entire desktop folder and PsychoPy has learned not to allow that.
Assuming that’s all correct, there will be a folder on your desktop called .git and you’ll need to go and remove that folder and its contents BUT because it begins with a dot windows will be hiding it from you. Open a file explorer window and go to your desktop, then tell it to Show Hidden Files and remove the .git folder