I've just seen this on Ubuntu 16.04 on an EeePC and in one start up configuration it always happens and autologin always fails.
It seems to be highly dependent on what else is happening as lightdm is starting. When the problem occurs looking at the lightdm log shows that it is trying to log using a normal PAM lightdm session rather than an autologin PAM session. This leads to failure because the account being authenticated has a password and no password is being passed to PAM and the user is intentionally absent from the nopasswdlogin group. Attaching /etc/lightdm/lilghtdm.conf, /var/log/lightdm/lightdm.log and PAM's /var/log/auth.log . ** Attachment added: "lightdm.conf" https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1250875/+attachment/4645855/+files/lightdm.conf -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1250875 Title: Lightdm sometimes fails to auto login Status in lightdm package in Ubuntu: Confirmed Bug description: Using ubuntu 14.04 and sometimes when I boot into ubuntu lightdm fails to auto login, and I must login manually in the unity greeter. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: lightdm 1.9.3-0ubuntu1 ProcVersionSignature: Ubuntu 3.12.0-2.7-generic 3.12.0 Uname: Linux 3.12.0-2-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.12.6-0ubuntu1 Architecture: amd64 Date: Wed Nov 13 14:33:18 2013 InstallationDate: Installed on 2013-10-10 (33 days ago) InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Beta amd64 (20131008) MarkForUpload: True SourcePackage: lightdm UpgradeStatus: Upgraded to trusty on 2013-11-04 (9 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1250875/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
