This question is a followup for this [one].1 I've identified the problem as being related to different xorg driver versions. My /etc/apt/sources.list file on the upgraded system is as follows: # deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ dists/precise/main/binary-i386/ # deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ dists/precise/r