Today an average email user receives around 50 to 100 messages per day. Regardless of whether you use your Outlook 2013 mailbox for personal or for business correspondence, a certain percentage of emails you get can be considered excessive. Naturally, the first example that comes into your mind, is spam, or, if your spam filtering is near-perfect, various subscription emails that need unsubscribing. However, there is another source of mess in a mailbox, and it is duplicate emails. Although Outlook 2013 is already an extremely sophisticated email client, duplicate email messages may still present a problem to its users.