With Outlook 2016, the software program changed in that the main database was no longer recognized because Spotlight does not recognize any name with special characters in it. When the software recreated the database, it automatically added dates with slash marks within the new identity. The reason is that in Mac Outlook 2011, users were able to recreate the Main Identity using the 'Rebuild the Database' program. Two of our department Users of Microsoft Office 365 Outlook for Mac found that once an upgrade from Office Outlook 2011 had taken place, they no longer were able to search within Outlook for emails to or from different contacts. Only one worked for me (Solution 2 below). I searched for and found at least 4 possible solutions. Our department upgraded from Mac Office 2011 to Mac Office 365 2016.
