Can't open Mailstore Home

I have an old users laptop that had mailstore home setup on to pull down emails from his previous company. We’ve migrated him to a new machine a few month’s back and he was asking if we could move the mailstore app with that database onto the new computer but when I open mailstore home, it complains that “Mailstore Home needs an archive to continue”. I see the .dat files in the c:\users\someuser\documents\mailstore home” directory but it’s looking for an .xml and . fdb file which I cannot seem to find. It was working last I checked. Am I at a loss here?