One remote user from work called me the other day saying her remote desktop client stopped working because of â€œthere are no terminal server client access licenses available for this computerâ€. Well, that’s easy, I walked her through and successfully deleted the MSLicensing registry key on her Windows Vista computer, and happily told her you can try it again now. But surprisingly, she replied a few seconds later saying no, still didn’t work. But this time the error message was different:
The remote computer disconnected the session because of an error in the licensing protocol
It’s surprising because having been using remote desktop client for ages this is the first time I saw the error message like this. Out of luck after a few checking here and there, I went to Google for help. Nothing had worked until I was landed to this Microsoft KB, Removing Terminal Server licenses from an RDP client. At the very bottom of this KB, it mentions:
If you delete the HKEY_LOCAL_MACHINE\Software\Microsoft\MSLicensing subkey on a client that is running Windows Vista or a later version, later attempts to connect to a Terminal Server may fail. Also, you receive the following error message:
An Error occured in the licensing protocol.
And suggests that to resolve this problem, right-click the Remote Desktop Connection icon, and then click Run as Administrator.Â
Bingo!! That was it. Did I mention that this problem was actually occurred on a Vista computer above? And it only happens on Vista or later OSs because:
By default, the remote desktop connection runs as a user with the lowest user permissions. By default, a restricted user does not have permission to write registry entries to HKEY_LOCAL_MACHINE. Therefore, attempts to rewrite the MSLicensing key fail. Starting Remote Desktop Connection with administrative credentials provides the permissions that are necessary to write the needed registry keys.