Microsoft has released an update for Office for Mac 2011, that provides the latest fixes to Office for Mac 2011. "This update fixes an issue that causes Outlook to crash or close unexpectedly sometimes when you import a .pst file that contains categories. Specifically, categories that have no category names assigned to them."
Also, featuring "improved reliability & stability, and a fix to the annoying bug that made you close Office AutoUpdate to be able to actually run the Office Update. If you've any applications that use Office, such as Endnote, or any other Office associated add-on that invokes one of the Office suite programs, 14.0.2 addresses an issue where the third-party program failed to get Office to load the appropriate document," KB2476509.
Microsoft Office for Mac 2011 14.0.2 Update requires computer running Mac OS X v10.5.8 or a later version of Mac OS X operating system.
To verify that the computer meets this prerequisite, click About This Mac on the Apple menu.
Download: Office for Mac 14.0.2 Update