In ~/Library/Mail the same folder structure seems to exist, with each POP or IMAP account listed, and then mboxes corresponding to mailboxes and so on, as before. But at least in IMAP accounts the user folders (mboxes corresponding to "folders" in Apple IMAP or "labels" in Gmail) are empty; all the mail files (emlx) seem to be in All Mail. Is this the default structure? Or have I got something special going on? In my old pre-Mav Mail folder it seemed the messages were in some kind of library structure sorta like iPhoto libraries and so on. It matters because I was backing up those individual mbox folders separately. Edit: seems some are kept in /Mail, but most in /Mail/V2. Dunno why both.