1. Go to your inbox
2. Select "all" messages (top tic box) even if there aren't any there.
3. Use the drop menu & select the option "mark as unread"
4. Click Go
5. Your notifications "unread total" should change to how many messages you have total in the inbox folder. (Private Messages: Unread 5, Total 5.)
6. Repeat #3 and select "mark as read"
7. Click Go
8. Your notification total should change to 0 (Private Messages: Unread 0, Total 5.)
If that dont work, a superadmin may have to clear the forum cache for it to clear the issue up.