Restict users for RDS

To deny a user or a group logon via RDP, explicitly set the "Deny logon through Remote Desktop Services" privilege.

To do this access a group policy editor (either local to the server or from a OU) and set this privilege:

1. Start | Run | Gpedit.msc if editing the local policy or chose the appropriate policy and edit it.
2. Computer Configuration | Windows Settings | Security Settings | Local Policies | User Rights Assignment.
3. Find and double click "Deny logon through Remote Desktop Services"
4. Add the user and / or the group that you would like to dny access.
5. Click Ok.
6. Either run gpupdate /force /target:computer or wait for the next policy refresh for this setting to take effect.