RDP: Allow multiple simultaneous connections

Patch the termsrv.dll file found in C:\Windows\System32 using a hex editor.
Find 39813C0600000F84F7400100 and replace it with B80001000089813806000090

Set the fSingleSessionPerUser DWORD Value at HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\ to 0.

Reboot computer.