Found this post here: http://askubuntu.com/questions/215842/ubuntu-12-10-sometimes-a-black- screen-after-boot:
I had almost the same problem, black screen at login :( I had to Ctrl+Alt+F1 and restart lightdm and then it worked perfectly, but it sucked a bit to do that all the time so this is what a did next sudo gedit /etc/rc.local before the "exit 0" line insert this line: service lightdm restart This worked for me,and i hope it'll work for you too. -- 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/969489 Title: lightdm tries (and fails) to start too early? Status in Upstart: New Status in “lightdm” package in Ubuntu: Confirmed Bug description: Sometimes lightdm comes up fine. Other times it appears to fail. x-0.log shows it tried to load 'nv' (rather than 'nvidia' which is what actually exists). When I then log into console and 'start lightdm', it comes up fine (on :1). I've not had it come up ok today, so I don't know if, when it comes up fine, it starts on :0. No idea if the lightdm.conf needs a change to 'start on'clause, or if this is just a case of a bad shipped config file (for module 'nv'). ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: lightdm 1.1.9-0ubuntu1 ProcVersionSignature: Ubuntu 3.2.0-20.33-generic 3.2.12 Uname: Linux 3.2.0-20-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.0-0ubuntu1 Architecture: amd64 Date: Fri Mar 30 13:40:27 2012 InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120323) ProcEnviron: TERM=xterm PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/upstart/+bug/969489/+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
