In the Appearance tool, we have the option to span a wallpaper across multiple displays.

On the Desktop it works fine:

Screenshot of spanned image on desktop

However, on the lock screen I see the same image repeated three times:

Screenshot of lockscreen

How do I span the wallpaper across displays on the lock screen? I don't see any option to do so in the appearance menu.

2 Answers 2


At this time this is not possible due to bug #1291359.

This issue is still present up to Ubuntu 16.04.

The most common thing to do at this moment is to show the default login screen/color.

You can do this by installing dconf Editor.
Open a terminal with Ctrl+Alt+T and type:

sudo apt install dconf-editor

or click dconf Editor Install dconf Editor to auto-open Software Center and click Install to install it.

Now we must grant LightDM permissions to access dconf Editor.

  • Gain root access, type your password (no visual feedback),and Enter.
    sudo -i
  • Allow user to create a connection to the X server for lightdm
    xhost +SI:localuser:lightdm
  • Switch to user lightdm
    su lightdm -s /bin/bash
  • Start dconf Editor

On dconf Editor, navigate to com > canonical > unity-greeter in the left pane.

  • Disable (untick) the value for 'draw-user-backgrounds' on the right pane.
  • While at it, you may want to disable 'draw-grid' (it disables the dotted grid layer).

Reboot to confirm changes.

sudo reboot

Note: from now on LightDM has permission to access the X server, so every time you open dconf Editor, LightDM already has access.
To revoke this access, issue the command xhost -SI:localuser:lightdm as root.

  • And what about using a different greeter? Could that work?
    – Alfro
    Aug 11, 2016 at 20:50
  • 1
    @Alfro I tried unity-greeter, lightdm-gtk-greeter, lightdm-kde-greeter but unfortunately they also do not offer any options to span the wallpaper on login screen. Aug 13, 2016 at 15:21
  • Note: I tried your approach and got the error dconf-CRITICAL **: unable to create directory '/home/tvbox/.cache/dconf': Permission denied. dconf will not work properly.
    – Elder Geek
    Aug 16, 2016 at 14:45
  • @ElderGeek I updated the answer. I have forgotten to allow LightDM to access the X server. It should now work. Aug 16, 2016 at 16:48
  • CLI method Error dconf-WARNING **: failed to commit changes to dconf: Error spawning command line. The GUI method works though.
    – Elder Geek
    Aug 17, 2016 at 14:14

Hm. To save you some poking around, I've tried Variety, dconf-editor, nitrogen, and CompizConfig with no luck. The closest I could get was setting a particular wallpaper for just the lock screen with dconf-editor.

Strangely, if you install gnome-tweak-tool there is a setting under Desktop that allows you to choose a separate mode and image for the Background and Lock Screen - but while the Background settings here affect my desktop, my tests with the Lock Screen settings don't make any change. It may be a lead, however, if you want to try and finagle Unity into submitting to Gnome (assuming the tweak options haven't just been broken from the start).

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .