Before upgrading to Ubuntu 16.04 from 14.04 I used to log into GNOME-flashback desktop session from GDM login prompt. After upgrading to Ubuntu 16.04 I had to remove GDM(along with nvidia proprietary drivers etc.) as it never starts(gets stuck at systemd prompt) and installed LightDM again. It was going on without further problem since then until today I tried to change the session to GNOME-shell from LightDM.

I clicked the desktop session chooser button at top-right of the little login box provided by LightDM greeter screen and it gave me a blank box instead of a list of desktop sessions. helpful lightdm greeter I managed to bring back the password prompt by clicking on hostname on the top left of the screen. But now I can only log into GNOME shell.

The steps I tried without success

  • Listing out possible desktop environments

    $ ls /usr/share/xsessions/
    gnome.desktop                   gnome-flashback-metacity.desktop
    gnome-flashback-compiz.desktop  ubuntu.desktop
  • manually creating a (possibly deprecated) /etc/lightdm/lightdm.conf with following content


    and subsequently after it didn't work

  • editing ~/.dmrc(which was present in system before this problem)


So now I'm stuck with GNOME shell as the only desktop environment. I want to go back to GNOME classic session and want to be able to switch between desktop environments when needed. Any help on this?

  • Tried using lightdm-gtk-greeter instead? install it and change it with update-alternatives
    – Anwar
    Aug 21, 2016 at 14:48
  • Ok, it worked. Lightdm-gtk-greeter shows the available desktop sessions lists and I'm able to log into gnome-flashback-compiz session.
    – Samik
    Aug 22, 2016 at 7:13
  • Do you want me to write that as answer or close the question?
    – Anwar
    Aug 22, 2016 at 9:17
  • Since no one upvoted the question it seems the problem is localized to my system. You can close it if you want.
    – Samik
    Aug 22, 2016 at 9:19

1 Answer 1


I guess your unity-greeter has messed up something. I have two solutions.

  • Reinstall it

    sudo apt-get --purge autoremove unity-greeter
    sudo apt-get install unity-greeter
  • Or Install lightdm-gtk-greeter instead. Install it with

    sudo apt-get install lightdm-gtk-greeter

    and change it as default using

    sudo update-alternatives --config lightdm-greeter

    and select the entry for lightdm-gtk-greeter and pressing Enter.

  • This will remove everything like: ubuntu-desktop* unity* unity-greeter* unity-scope-virtualbox* unity-tweak-tool* and you need to reinstall all that shits! Of course if you want your PC to work..
    – Kerem
    Sep 2, 2017 at 19:55

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