Leave the old version installed and install the new one. Update: There’s no need to uninstall an old version of Office for Mac before installing a new one. Much to our surprise, uninstalling Office 2011 for Mac is a terribly complicated affair. We decided to give it a whirl and wanted uninstall Office 2011 to avoid any conflicts. Microsoft has been readying its latest update to Office for Mac, and recently released its first preview.