Email Disappears

This has been going on for several months.  If I send and email to myself, it flashes in the inbox for a couple of seconds and then disappears.  It is nowhere!  I have no rules or filters applied to Outlook.  At times random email from others does the same thing.  I just did an online repair of Office.  That didn't help.  There are literally hundreds of other people on the internet who have the same problem.  No viable solution is evident.  This is a serious problem.  Can anyone help?