Recently Outlook has started marking unread messages as read if the inbox is open. This never used to happen before. In preferences under reading tab I have Mark mail as read - When opened in a separate window as it always has been. Its the same pop email acct I have had for years and to the best of my knowledge I haven't made any changes. What is causing incoming unread emails to be marked as read? Please note that I stated above that I have Mark mail as read - When opened in a separate window selected.