For information about this update, see MS16-070: Description of the security update for Office 2016 for Mac: June 14, 2016. If your Outlook installation is not at version 15.23 or a later version, install the June 14, 2016, update for Outlook 2016 for Mac or a later update.View the version number that is listed.On the Outlook menu, select About Outlook.Step 1: Check the Outlook for Mac version number Then, disable the preview feature for encrypted email messages by running a command in Terminal. To fix this issue, update Outlook 2016 for Mac to version 15.23 or a later version. In Outlook 2016 for Mac, when you navigate to a folder in which several encrypted email messages are displayed in the message list, Outlook freezes or experiences other performance issues. Outlook 2016 for Mac freezes on email folders that contain several encrypted messages
