I just found a folder named, “Orphaned Files”, and it contains a few hundred emails from 2007/2008, for a mailbox that is not a part of this particular database. I normally archive my email to an email specific database, and am not sure where these files came from. I’ve run a Verify & Repair on the database, and no errors were detected. Is it OK to move these Orphaned Files to the Trash and Empty?
The orphaned emails are probably the result of e.g. crashes, force quit, power outages or other severe issues while importing/archiving emails. You could move them to the desktop first and afterwards import them to the same database to check whether these are duplicates and not necessary anymore.