Ubuntu – Ubuntu 18.10: Screen lock options grayed out

18.10gdmlock-screenvirtual-console

Recently upgraded to Ubuntu 18.10, having two problems.

Easiest to explain: when I open "settings", go to "privacy", select "screen lock", I get the popup window with the screen lock settings, but everything is grayed out:
screenshot of grayed out popup.

Second issue: If I step away from the machine for long enough (seems to be 5 minutes), the screen blanks. Hitting a key or moving the mouse wakes it up. But when it wakes up, the only things on the screen are the icon bar at the left and the top bar with status icons on the right end. The rest of the screen is blue, not my normal lock screen image. The screen isn't locked, it doesn't prompt for a password, it's just…blue.

I can move the mouse pointer around the screen, the icons react if I click on one, I can bring up the popup with volume/brightness controls on the top bar. But if the pointer is on the blue background, neither left nor right button clicks do anything.

Now, if I press ctrlaltF1 from there, I get a lock screen where I can enter my password. Then I get the blue screen back, but if I press ctrlaltF2 I get my normal screen (with running applications) back.

ctrlaltF2 without going through the lock screen first does nothing.

I'm not finding anything while searching that matches either of these sets of symptoms. Suggestions?

Best Answer

It is likely that your lock screen has been disabled. You can enable the lock screen with the following command in the terminal.

gsettings set org.gnome.desktop.lockdown disable-lock-screen false

If you want to enable the lock screen with a GUI you can do this with dconf-editor. You can install dconf-editor in the terminal with the following command.

apt install dconf-editor

Once you have dconf-editor installed enable the lock screen with the following steps.

  1. Open dconf-editor.
  2. Browse to /org/gnome/desktop/lockdown/.
  3. Find disable-lock-screen.
  4. Toggle option from On to Off.

Thanks to jugs for providing this solution at https://bbs.archlinux.org/viewtopic.php?id=227258