All of a sudden, my regular email box shows an unread number of emails yet I've read all of them. At this point, I'm up to 13 unreads. What's causing this?
This is your Inbox?
Try Rebuild. Click on the Inbox so it is selected, then click on Mailbox in the menu bar. Rebuild is the last item in the drop down.
In the same way you can Rebuild any mailbox, not just the Inbox.
So where did all my messages go?
Retrieving data ...