Shortly after you start Microsoft Outlook for Mac 2011 on Mac OS X El Capitan (version 10.11), Outlook hangs when it tries to sync with the server. The Spinning Wait cursor is displayed, and the application status is displayed as "Not Responding."
Note Outlook for Mac 2011 does not hang when you're working offline or when no accounts are added. This issue occurs only when Outlook tries to sync an account with the server.
To fix this issue, install the Microsoft Office for Mac 2011 14.5.6 update. For more information about this update, go to the following article in the Microsoft Knowledge Base:
This issue occurs in Outlook for Mac 2011 version 14.5.5 and earlier versions when they are running on Mac OS X El Capitan (version 10.11). The issue does not occur on Mac OS X Yosemite (version 10.10) and earlier versions.