Issue:
– You want to remove an Office 2011 for Mac license from a machine,
– You want to re-install Office 2011 for Mac but can’t find your installation code.
To Remove License:
To remove an Office 2011 license from Mac OS X, navigate to: Macintosh HD\ Library\ Preferences\
Delete the file: com.microsoft.office.licensing.plist
To Backup the license to re-install:
Just copy the com.microsoft.office.locensing.plist file to a safe location, and then place the file BACK inthe ORIGINAL location AFTER you have re-installed the Office application.
Source: Microsoft Support – How to completely remove Office for Mac 2011