Duplicate Emails also decrease the performance of the app. It leads to taking lots of space and making files unmanageable. There are several reasons for email duplication in Outlook. For example, Third-party antivirus, Improperly set mailbox, and much more. There are two types of techniques for Deleting Duplicate Emails from Outlook – Manual Methods and the professional method. If you are looking for solutions to remove duplicate Emails in Outlook, read the article further.