After an unknown problem occurred I was asked to run a database rebuilt.  This was done, Outlook opened, then wanted another database rebuild.  this happened a few times.  Now Outlook will not open at all.  I restarted my iMac in Safe Mode, tried opening Outlook (latest version with latest Mavericks), it indicated it was setting up the identity, and then closed.  No error messages.  I have tried everything to get Outlook to open.  I found a “Hail Mary” solution that was posted by an MVP, it was what I followed, without success.