Note to self: Finally figured out how to get Mail.app on OS X Mavericks to behave when I am trying to delete or move mailboxes that are “On My Mac”. The Secret is there was an ACL set that was preventing the everyone group from deleting anything.
drwxrwxr-- 16 joe staff 578 Feb 27 08:56 V2
0: group:everyone deny delete
There may be undesired consequences from doing this…proceed at your own risk.
To fix this:
1. Quit out of Mail.app
2. Open terminal, and do the following.
chmod -R -a "everyone deny delete" V2
That will remove the ACL from all of the mailboxes and folders. As I said, might have a negative side effect.