We have a user that has an issue where Outlook 2013 will crash when using the scheduling assistant with external addresses. For some reason it doesn't crash when using my external email address but every other email address we have tried will cause it to crash. I have tried disabling all the add-ins but it doesn't make a difference. I have also tried running the outlook diagnostic utility which disabled add-ins and other things but it still crashes after running that.
The only thing that worked was starting Outlook 2013 in safe mode.
Any ideas?