What I am trying to do is to send emails (which is HTML form) to each client. When client opens that email, goes to web server process somethings. After that process, that email has to be closed and deleted automatically. The problem is web app does not have permission to delete client's email. it requires client machine install my DLL which I don't want to. I guess .net framework configuration or specific app role only effect on server machine or client one. is that right? Hope to get help from you. Thanks a lot.