Boot hangs at login screen

[peterzay]

Boot hangs at login screen.

Cannot type any password. Drop down menu for shutdown not available.

Only exit possible is to press the PC power button for 5 seconds to do a hardware shutdown.

The problem is intermittent and not reproducible.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity-greeter 0.2.8-0ubuntu1.4
ProcVersionSignature: Ubuntu 3.2.0-34.53-generic-pae 3.2.33
Uname: Linux 3.2.0-34-generic-pae i686
ApportVersion: 2.0.1-0ubuntu15
Architecture: i386
Date: Fri Dec 21 05:47:15 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: unity-greeter
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Srini RamaKrishnan (cheeni)]

`sudo service lightdm restart` is a better work around than rebooting.

[Ben de Mora (ben-demora)]

This happens around once every two or three boots. Running Ubuntu 13.10 on a Lenovo T420 laptop.