Outlook hangs / freezes frequently
I'm seeing a number of complaints where Outlook freezes or hangs and in many cases the issue went away when hardware graphics acceleration is disabled.
You can disable the use of Hardware Graphics Acceleration (for the entire Office 2013 suite) from the Options dialog of any Office 2013 application. Each application that is open will need to be closed and restarted after changing the setting.
In Outlook, go to File, Options, Advanced and select Disable Hardware Graphics Acceleration, near the bottom of the dialog.