Messages coming into the inbox immediatly go away, not in deleted

[The Baum]

A co worker of mine has messages coming into his inbox, they sit there for a
few minutes and then dissapear. They are not in his deleted folder and when
I go to the original server via the internet, they are in there.

 

[K. Orland]

Is the user filtering his view, perhaps by unread messages only? If he's
previewing messages and Outlook is configured to mark them as read after X
seconds, this could be the problem.

View > Current View > Messages (is what should be checked)