Following works for me.In the “Search Current Mailbox (Ctrl+E)” box, type: read:no and hit Enter.When it shows “Find More on Server” link, click it. Then the unread email(s) should appear.EDIT: Works with Outlook 2016 as well you can see the image reference for your further help. http://superuser.com/questions/577858/how-to-fix-the-wrong-number-of-unread-emails-flag-in-outlook-2013