I found a workaround that works fine for my i5 laptop with nvidia optimus card.
Install the latest nvidia drivers and reboot. After that the user switch does work again. sudo apt-get install nvidia-319 nvidia-settings-319 nvidia-prime -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1247189 Title: [13.10] Ubuntu freezes completely when switching user To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1247189/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
