Hi Ben,
Thanks for your patience.
I got an update from the assisted team that there is a new update released for Outlook for Mac, and it is suggested you try the solution in the following artcile:
http://support.microsoft.com/kb/3025088
If the issue still exists, I've sent a private message to you, please check it if you do have tried the soltuion above.
To check the private message:
• Go to the your details section on the right side of the community site.
• Click Private messages.
• Click the subject title of the response to read the message.
• You can reply by using the form that displayed.
• Click Submit Reply.
Thanks again for time and efforts.
Regards,
Kevin Huang