On Mountain Lion mail, when I add a POP3 account, let it check mail, and then click archive on some messages...it creates two "On My Mac" folders under archive. They are exact duplicates, and deleting one also deletes the other. Anyone else experiencing this and know how to fix it? On Apple's official support forums, there is a thread about this https://discussions.apple.com/thread/4165476?start=0&tstart=0 but no one has reported a fix yet. The only solution mentioned is to create another folder and use that instead of the archive button...because the second you delete them, when you archive something else, it recreates the two folders.