The Office 2011 SP2 release improves database resiliency and detects inconsistencies that went unnoticed prior to this release; however some users have experienced issues related to corrupted databases after the latest updates. We have support and workarounds available for you in the following situations:
Before installing Office 2011 SP2, use the following article to rebuild your database in 14.1.4 to ensure that your database is in a good state for the upgrade to safely apply: Rebuild the Outlook for Mac 2011 database to resolve problems
If you’ve already installed Office 2011 SP2, and you receive the message ‘Please upgrade the Office database,’ please check out the following article for the workaround: Outlook 2011 start error: “Please upgrade the Office database”
We apologize to users who were affected by this issue. Users who successfully updated report very noticeable improvements including performance and a host of other fixes.