Outlook 2003 - Missing Emails wrote:

The Auto Archive feature was turned off. Trying to go through the
Deleted folder and no missing emails there as well.

I read few posting from other groups indicating that some hidden pst
files may be found. What are they usually called in ".pst"?

A PST is the file extension used by the file(s) that hold your Personal
Folders (Inbox, Outbox, Calendar, Contacts, etc.). Its default location is
a hidden folder, but you can easily see the path to that file with FIleData
File Management.
--
Brian Tillman