autologin fails for administrator user

[Steve Holmes]

I had two user accounts on the machine, an administrator and a normal user.
I edited a conf file in /etc/lightdm to auto login the unprivileged user, which worked fine. I then deleted the unprivlieged user and changed the config file to autologin the remaining user. This does not work, a password prompt is always presented to this user.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: lightdm 1.14.2-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.19.0-31.36-generic 3.19.8-ckt7
Uname: Linux 3.19.0-31-generic i686
ApportVersion: 2.17.2-0ubuntu1.7
Architecture: i386
CurrentDesktop: MATE
Date: Fri Oct 30 20:06:14 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-09-26 (33 days ago)
InstallationMedia: Ubuntu-MATE 15.04 "Vivid Vervet" - Release i386 (20150422.1)
LightdmGreeterLog:
 ** (lightdm-gtk-greeter:905): WARNING **: [PIDs] Failed to execute command: upstart

 ** (lightdm-gtk-greeter:905): WARNING **: Failed to load user image: Failed to open file '/home/bouncysteve/.face': Permission denied
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Robert Ancell (robert-ancell)]

The relevant parts from the LightDM log are:

[+1.01s] DEBUG: Seat seat0: Display server ready, starting session authentication
[+1.01s] DEBUG: Session pid=857: Started with service 'lightdm-autologin', username 'bouncysteve'
[+1.09s] DEBUG: Session pid=857: Authentication complete with return value 0: Success
[+1.09s] DEBUG: Seat seat0: Session authenticated, running command
[+1.09s] DEBUG: Registering session with bus path /org/freedesktop/DisplayManager/Session0
[+1.10s] DEBUG: Session pid=857: Running command /usr/sbin/lightdm-session mate-session
[+1.10s] DEBUG: Creating shared data directory /var/lib/lightdm-data/bouncysteve
[+1.10s] DEBUG: Session pid=857: Logging to .xsession-errors
[+1.80s] DEBUG: Activating VT 7
[+1.80s] DEBUG: Activating login1 session c1
[+1.80s] DEBUG: Seat seat0 changes active session to c1
[+1.80s] DEBUG: Session c1 is already active
[+1.82s] DEBUG: Session pid=857: Exited with return value 1

Which says the autologin did complete, but the session exited for some reason. You may be able to find out why by looking at ~/.xsession-errors. Otherwise the issue is probably in mate-session.

[Steve Holmes (bouncysteve)]

The user's home directory was encrypted, so signing in without a password is not valid.