Ubuntu 14.04 has just recently started doing this to me too about a week ago, today being 2015-04-22. I keep Ubuntu upgraded on this 64bit PC (Intel i5) to the latest state nearly all the time.
I wonder if this helps: When I turn on the power (with the BIOS is set to start the PC when power resumes) I often see my desktop for an instant before the system flips to the login screen. If however I reboot the machine without downing the power, the auto logon works OK. Happy to do any diagnostics as directed. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1250875 Title: Lightdm sometimes fails to auto login To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1250875/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs