Comment 27 for bug 529882

Similar issue on Ubuntu Lucid 64-bit, upgraded from karmic on a Thinkpad x200. Switching users typically works a few times, then I get the black screen. Occasionally there is a mouse pointer, but usually not. I can't switch to a virtual terminal, and have to ctrl-alt-backspace, which typically brings up the list of users, with the user I was trying to switch to no longer logged in.