Aaron-McLeod wrote:

I have a user who is missing several (random) email messages from his
PST. The folders are NOT being Archived, even so, the items were not
old enough to be archived. The search companion and Windows Desktop
Search are unable to find them. The user is 100% certain these items
were not deleted, and do not appear in Deleted Items folder. The PST
file is approximately 125 MB with an Archive PST at approximately 400
MB.

There is no way I know for Outlook to lose messages "at random" without
being affected in other ways. The most likely cause if a view hiding the
messages in question. With Outlook closed, run the Inbox Repair Tool
(SCANPST) amd try starting Outlook once with the /cleanviews command line
switch.
--
Brian Tillman