Cannot mark email messages as un-read

Whenever I right click on an email and click mark as unread it will do so, but the second I look at another email the one I marked as unread turns to read again. I am not selecting this email in the main reading pain, just any email I right click on.

Hi, make sure you have the latest .NET version 2 SP2 installed or at least .NET 3.5
http://www.microsoft.com/download/en/…