• I have Ubuntu. Because of its extraordinarily slow speed (especially after upgrading to 16.04 from 14.04, almost as slow as Windows), I installed lubuntu-desktop and now use Lubuntu. The change has greatly speeded my computer.
  • I am able to choose whether to boot into Ubuntu or Lubuntu each time I log in.
  • After this change, in Lubuntu, the automatic suspend would not work because it asked for the password. I fixed this using the solution to Authentication required before suspend.


When I resume from automatic suspend, I am greeted with an unusual login screen, which has only three elements:

  • The day and time
  • The title "Light Display Manager"
  • A prompt to enter a password without a user being displayed

When I enter my password, the prompt responds with, "Incorrect password". I have, of course, tried multiple times and typed my password carefully.

I cannot proceed from that screen, and even Ctrl+Alt+Delete doesn't work. I have to use REISUB. EDIT: I can also sign into a console (Ctrl+Alt+F1) and sudo reboot.

Extra notes

If I suspend manually, or if I use Ubuntu, the computer resumes properly with the correct login screen, accepting my password and allowing me to continue. Only the automatic suspend from Lubuntu gives this problem.


How do I get the computer to resume correctly from automatic suspend when using Lubuntu?

  • The lubuntu-desktop metapackage installs the xfce4-power-manager so maybe the problem is that both xfce4-power-manager and gnome-power-manager are active. Try to disable suspend from the gnome-power-manager and enable it at xfce4-power-manager. – Thanos Apostolou Aug 27 '16 at 14:44
  • Do you see the same issue with a pure Lubuntu installation? – DK Bose Aug 28 '16 at 1:27
  • @ThanosApostolou : Thanks, but unfortunately it doesn't help. – Paddy Landau Aug 28 '16 at 12:36
  • @DKBose : Sorry, I'm not going to reformat my drive and do a full installation. I don't have that sort of time! – Paddy Landau Aug 28 '16 at 12:37
  • Hmmm light-locker is also installed with lubuntu-desktop, so maybe try to disable it or remove it by sudo apt purge light-locker. – Thanos Apostolou Aug 28 '16 at 13:39

This solved my problem

sudo apt remove gnome-screensaver

There is a conflict between screensavers as LightDM starts up gnome-screensaver when the device goes into suspend at the lock/login screen.


For a quick temporary fix:

  • Login to a terminal, use CTRL+ALT+F1 or ...+F2 etc.

  • Kill light-locker as admin: sudo pkill light-locker

  • this only solves the problem temporarily – João Pimentel Ferreira Jan 15 at 20:40
  • It helped me when I needed to be quick. Too bad I pressed switch user which somehow killed my old session. – Martijn Weterings Jan 25 at 16:25

Edit /etc/lightdm/users.conf as administrator. In the [UserList] section, make sure you have

hidden-users=nobody nobody4 noaccess lightdm

(user lightdm is often missing)

  • 1
    Thank you for the reply, @ced. I had other issues that forced me to reinstall Lubuntu from scratch. So, I can't check if your solution would have worked :( Incidentally, you used Windows backslash instead of the normal forward slash for the path :D – Paddy Landau Jul 25 '17 at 14:57
  • Oops. I typed the path manually. Old habits are difficult to quit. Ashamed. – ced Jul 25 '17 at 16:34
  • tried and doesn't work! – João Pimentel Ferreira Jan 15 at 20:28

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