After upgrading to Mountain Lion, some Mailboxes have been moved. I previously had some mailboxes in the "On My Mac" section. They are no longer there, but instead are now under the main Mailboxes heading. There is a lot of important content in this mailbox.
I am wondering what the significance of this change is. For example, does that mean these mailboxes would now be back on the IMAP server? This is not my intent. And in looking on the IMAP server, it actually appears these mailboxes are not there.
In addition, under the mailbox that was so moved, the first level has two "On My Mac" subfolders. However, when clicking on either of them, the same expansion occurs. This makes me think that the duplication is erroneous and that in fact there is only one such folder.
Trying a rebuild on at any point of the moved structure seems to "do nothing." Doing a Synchonize on the IMAP server also seems to have no effect.
Can anyone explain the following: 1. Why did this mailbox get moved? 2. How does the Mail program keep straight what is "On My Mac" and what is on the IMAP server? 3. Why is there a duplication of the subfolder? 4. Any other problems I should be aware of due to this issue?