In Windows XP if you have a problem with your RDC client license, you can delete the HKLM\Software\Microsoft\MSLicensing key to force the license to rebuild itself on reconnection. If you try the same thing on Windows Vista or Windows 7, when you try to reconnect to the server you get this message:
The remote computer disconnected the session because of an error in the licensing protocol. Please try connecting to the remote computer again or contact your server administrator.
and the MSLicensing key does not reappear in the registry. What causes this and how to avoid it?