Boot hangs on post-boot + pre-login black screen

[Srini RamaKrishnan]

Upon logging in to the console with ctrl-alt-f1 top revealed unity-greeter being run by user lightdm was the culprit. Immediately after issuing `sudo killall unity-greeter` the screen switched to graphical boot and I was presented with a login screen and everything proceeded normally from there.

https://bugs.launchpad.net/ubuntu/+source/unity-greeter/+bug/1092858 seems to be a duplicate of this.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: unity-greeter 13.04.2-0ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-26.38-generic 3.8.13.2
Uname: Linux 3.8.0-26-generic x86_64
ApportVersion: 2.9.2-0ubuntu8.1
Architecture: amd64
Date: Tue Jul 9 21:32:30 2013
InstallationDate: Installed on 2013-07-02 (7 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
SourcePackage: unity-greeter
UpgradeStatus: No upgrade log present (probably fresh install)

[Srini RamaKrishnan (cheeni)]

`sudo service lightdm restart` is a better work around than`sudo killall unity-greeter` .

[Launchpad Janitor (janitor)]

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

[Ben de Mora (ben-demora)]

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