Problem:
"The problem occurred when moving my back-up to a new location. Somehow the MailStoreFileGroup.fdb file got corrupted. To cut to the chase is there a way to manually repair the file for my latest database back-up is to old for my comfort. I would rather repair the database and have excess to all my archived mails including the including the possibility of it going wrong. Then on forehand back up from an older back-up and missing those essential mails."
Resolution:
Thanks to MailStore Community powered support: