I’ve come across this a few times recently at.   A remote desktop session from an XP machine to a Vista or Windows 7 machine, will leave the screen on the remote PC blank apart from the cursor.

Up until now, the only solution was to reboot the PC to get at a log in screen.

Well it appears that the problem is related to smart cards of all things!   Especially bizarre as the customer didn’t use them?   When you start a remote desktop session, go into options, and then Local Resources.    Press the “More” button and you’ll see smart card ticked.    If you untick this option, the blank screen no longer happens!