No login widgets after LTS upgrade 12.04->14.04

[Olivier Mehani]

I just upgraded a 12.04 LTS to 14.04.

After rebooting, I get to an empty login screen, with no widgets to select the user or enter the password. Blindly hitting enter and entering the password successfully logs me in, and the session starts.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity-greeter 14.04.10-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-36.63-generic 3.13.11.6
Uname: Linux 3.13.0-36-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.4
Architecture: amd64
Date: Tue Sep 16 02:53:00 2014
InstallationDate: Installed on 2013-07-17 (425 days ago)
InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130213)
ProcEnviron:
 TERM=xterm
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=fr_FR.UTF-8
 XDG_RUNTIME_DIR=<set>
SourcePackage: unity-greeter
UpgradeStatus: Upgraded to trusty on 2014-08-30 (16 days ago)