In the process of trying to clean up my Apple Mail system I renamed my main Reference Mailbox folder where I store all archived messages. Rebooted after the rename, and continued on for the last couple of days. I went to look for something in it and now that mailbox is totally empty!
Where have all my mesages gone?
I found links to issues with that rename process from many years ago on Lion but nothing newer.
Try rebuilding the mailbox.
If that doesn't work, try re-indexing the mailboxes. This can take awhile if you have a lot of mail.
Reindex messages For El Capitan, try looking in V3. Sierra use V4. High Sierra use V5.
Reindex messages (2) See post by Linc Davis
Nope, Didn't work at all. Ended up going to an old backup off Time Machine and accepting the lost messages that came in and were filed between when I noticed the problem and the backup I restored.
rename mailbox lost all mails
