Clock on login screen in 24-hour format, desktop in 12-hour format? 18.04 Upgrade

Question

Recently upgraded from Ubuntu 16.04 to 18.04. As I have been setting up my GNOME desktop, I changed my clock to a 12-hour format (AM/PM) in System Settings. However, my login screen still shows the time in 24-hour format.

Overall I have had a lot of trouble trying to configure the GDM shell of the login screen. Many old posts regarding management of things like background, appearance, and behavior seem outdated and don't work. Additionally, having upgraded (instead of a clean install) I can't browse my files to find any obvious configuration file to edit. Gnome Tweak Tool can't seem to manage anything related to the login screen either.

Any suggestions on how I can change settings and configure the GDM login screen environment on 18.04?

Solution

I had the same problem and was able to cure it by adding the following lines to /etc/gdm3/greeter.dconf-defaults:

[org/gnome/desktop/interface]
clock-format='12h'

Comments

[UnKNOWn]

can you share your /usr/share/gnome-shell/themes/ubuntu.css file..I think lot of user who upgraded from 16.04/17.10 to 18.04 have this issue with GDM. the file i asked seems to be diffrent than what is coming with freshinstallation of 18.04.

[UnKNOWn]

you can change the time format with dconf tool.

[UnKNOWn]

Hi, as a quick test, take a backup of your file /usr/share/gnome-shell/theme/ubuntu.css and replace it with we.tl/I2y8Mev6Dx. Reboot the system and see if GDM changes. if not replace the backed up file back in /usr/share/gnome-shell/theme/ubuntu.css. Please let me know once you test it.

[Tugg]

Hey PRARP, I tried replacing my ubuntu.css file with the copy you provided, but no change. I also see a gdm3.css file, but that seems to be tied to my PopOS theme on the desktop environment.

[UnKNOWn]

are you using PopOS theme? can you share your /usr/share/gnome-shell/theme/ubuntu.css file please?

[UnKNOWn]

gdm3.css must be linked to /usr/share/gnome-shell/theme/ubuntu.css file. Then only you can see the difference. I assumed that you did not install any GDM3 Themes after you upgraded from 16.04 to 18.04. In this forum i have seen a question related to our topic. in that i observed his GDM behaviour also did not change.please go through these two pics we.tl/QgvXt4JlQX. Also go through this askubuntu question askubuntu.com/q/1041774/739431

[Johan Larsson]

Thank you! This works on Pop_! OS 21.04.