Server 2012 refusing RDP connections (no licensing)

Problem:

“The remote session was disconnected because there are no Remote Desktop License Servers available to provide a license”

Solution:

(h/t Lui P c/o http://social.technet.microsoft.com/Forums/windowsserver/en-US/797ab295-aa48-4b73-baa9-4eb7a255ea70/server-2012-refusing-rdp-admin-connection-no-licensing)

1. The graphical management tools for RDS Session Host Management are disabled when not operating a Domain (why?). The fall back is configuration via group policy:

Local Computer Policy -> Computer Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host -> Licensing
Use the specified RD license servers = <server IP>
Set the Remote Desktop licensing mode = Per User

This got us to a stage where Licensing diagnostics looked good and no related local errors showed up in the server logs but remote sessions were still refused, leading to…

2.  Force-removing the RDS licensing time-bomb registry entry:

computer\hkey_local_machine\system\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod

RegEdit alone couldn’t do it. It had to actually be run under highest privileges with the help of Sysinternals: psexec -s -i regedit.exe

After another reboot things seem to be working now.