That's a known bug in nVidia drivers. It will not happen if you disable desktop composition:
go to system settings -> visual effects -> disable desktop composition.
http://forum.infognition.com/index.php/topic,194.msg605.html#msg605http://forum.infognition.com/index.php/topic=202.msg604#msg604The problem is related to multithreading. Since we've changed how our threads synchronize in SR, it will probably go away in version 1.9.4 coming soon.