Comment 17 for bug 321311

I've had this a occasionally with Jaunty, including just now, so it isn't fixed. gnome-screensaver was taking up 99% of CPU while it 'checked my password'. Killing gnome-screensaver didn't work - the X window didn't redraw itself, but just stayed stuck on a black screen with a white box where the 'Checking your password' window used to be. I had to reboot.