Password textfield missing when unlocking

[Ray DeCampo]

Intermittently the password textfield will be completely missing from the unlock screen. The user's name appears and the background graphic which usually surrounds the textfield is present, but the textfield itself is missing. This typically happens when multiple users are logged into the computer. Unfortunately I do not have reliable steps to repeat the problem.

There are a number of workarounds. Sometimes I can use ctrl-alt-f7 or -f8 to switch to another user, log that user out and get to the log in screen with all the users listed. Then the original user can log in. Sometimes it is necessary to switch to ctrl-alt-f1 and restart lightdm. Sometimes I need to log into the machine remotely and restart lightdm. Sometimes all of these fail and it is necessary to restart the computer.

If there is something I could do to gather more information the next the computer is in this state, I would be happy to do so. Unfortunately I cannot run ubuntu-bug while the problem is exhibited, as there is no access to the GUI.

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu

Description: Ubuntu 14.04.1 LTS
Release: 14.04

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center

unity:
  Installed: 7.2.2+14.04.20140714-0ubuntu1.1
  Candidate: 7.2.2+14.04.20140714-0ubuntu1.1
  Version table:
 *** 7.2.2+14.04.20140714-0ubuntu1.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     7.2.0+14.04.20140416-0ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

3) What you expected to happen

The unlock screen would contain a textfield to accept the user's password.

4) What happened instead

The unlock screen contained no place to enter the user's password.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.2.2+14.04.20140714-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.13.0-35.62-generic 3.13.11.6
Uname: Linux 3.13.0-35-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,regex,imgpng,move,place,animation,vpswitch,grid,session,resize,snap,gnomecompat,workarounds,mousepoll,unitymtgrabhandles,wall,expo,ezoom,fade,scale,unityshell]
CurrentDesktop: Unity
Date: Sat Aug 30 22:16:21 2014
InstallationDate: Installed on 2014-05-25 (97 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)