Note: This feature only works well in enterprise environments that use a Microsoft Exchange Server.
Recipients who receive your message via other services like Yahoo!
or Gmail will still be able to forward your message.
Thats done, restart client and user should connect now.
FAQ
Why is thePermissions option missing or grayed out from my version of Outlook?
This feature is only available in the Pro or Pro Plus versions of Microsoft Office.
If I use this method, is there still a way recipients can forward my email?
Its not a foolproof way to prevent message forwarding.
It only provides a layer of protection from forwarding the message.