Outlook deleted the satellite file
Outlook security automatically deletes some file types when received as attachments. This includes Microsoft Access databases or mdb files. If your practice is sending you an mdb file as your satellite data file, ask them to re-send it in zip format. To do this, they should use the Maintenance > Zip & Email function. Outlook does not usually delete zip files, and you'll be able to read this using the Maintenance > Restore function in AA.