Configure Permissions using PowerShell
When Remote Desktop Session Host Configuration is unavailable, such as with Server 2012(R2)
This configuration can be set using PowerShell via WMI method
(
get-WmiObject -Namespace "root/cimv2/terminalservices" -Class win32_tspermissionssetting|Where-Object {$_.TerminalName -eq "RDP-Tcp"}).AddAccount("domain\customGroup",2)
The second parameter of the AddAccount determines guest(0),user(1),full(2) access, reference: msdn.microsoft.com/en-us/library/aa383815%28v=vs.8...
wmic /namespace:\\root\CIMV2\TerminalServices PATH Win32_TSPermissionsSetting WHERE (TerminalName ="RDP-Tcp") CALL AddAccount "server\group",1
(Get-WmiObject Win32_TSAccount -Namespace root\CIMV2\TerminalServices -Filter "TerminalName='RDP-Tcp' AND Accountname='server\\group'").ModifyPermissions(7,1)