Outlook freezes when trying to send a message

I have a user that is having her Outlook hang after she clicks on the ‘Send’ button. I’ve looked in event viewer and found this event ID (5000) message:
EventType officelifeboathang, P1 outlook.exe, P2 12.0.6300.5000, P3 ntdll.dll, P4 5.1.2600.2180, P5 NIL, P6 NIL, P7 NIL, P8 NIL, P9 NIL, P10 NIL.
When I googled it the only partially relevant answers had to with the Outlook Calendar which the user wasn’t using. Does anyone else have any recommendations? Microsoft was clueless. Thanks.