Ubuntu 20.04 login screen doesn't appear on the primary screen

I don't understand why this important and many users concerned bug (easy to solve) exists since so many years and all the discussions refer to mark something as duplicate and outdated. This bug still exists in my fresh installation of ubuntu desktop 20.04 from yesterday. My tv is the primary screen, notebook via hdmi is open for powerbutton. Login screen appears unreadable for me on the build in notebook screen.

2 Answers

I have fixed the problem with these line of code:

sudo cp ~/.config/monitors.xml ~gdm/.config/monitors.xml

It only works if the desired monitor has been marked as primary first.

I had to do some additional steps:

If you haven't done it yet, go to Settings → Devices → Displays and set your primary monitor. Save your settings.

Open a terminal and run the following:

sudo cp ~/.config/monitors.xml ~gdm/.config/monitors.xml
sudo chown gdm:gdm ~gdm/.config/monitors.xml
sudoedit /etc/gdm3/custom.conf

In the file uncomment WaylandEnable=false, and save.