Your log shows it working, but I suspect that was generated after you re-installed unity-system-compositor.
I think the problem is /etc/lightdm/lightdm.conf.d/10-unity-system- compositor.conf which is enabling unity-system-compositor even after you have uninstalled it. This file might have been manually edited by you. LightDM should fall back if it is not installed, but perhaps something else is going wrong. In short, purge unity-system-compositor and check that no configuration in /etc/lightdm/ is referring to it. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1263533 Title: Cannot start without unity-system-compositor Status in “lightdm” package in Ubuntu: New Bug description: I can only start lightdm when usc is installed. I already tried purging lightdm but still no difference. Even manually executing "sudo start lightdm" doesn't work. However, I can still call "startx" and get an xsession running. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: lightdm 1.9.5-0ubuntu1 ProcVersionSignature: Ubuntu 3.13.0-0.9-generic 3.13.0-rc4 Uname: Linux 3.13.0-0-generic x86_64 ApportVersion: 2.12.7-0ubuntu3 Architecture: amd64 CurrentDesktop: Unity Date: Sun Dec 22 20:56:30 2013 EcryptfsInUse: Yes InstallationDate: Installed on 2011-05-12 (954 days ago) InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1) SourcePackage: lightdm UpgradeStatus: Upgraded to trusty on 2013-11-11 (41 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1263533/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
