Zorin 18 Core
Wayland
Radeon 7700XT
Happens three times now, let the computer running for a Steam download. After 5 minutes i found it at the GDM login screen. Okay why not, it's locked and i can unlock it.
But that's wrong, the computer has crashed to GDM, every open program was forced killed. Brave offered to restore the latest pages, Steam is reset to 0 with the download. Using the computer for watching YT or Prime never cause a crash to GDM.
Ideas are welcome
Is Steam installed as .deb or Flatpak? Did You take a Look in the Logs? Did You see it by Yourself? I mean sitting by it and look what is happening?
Screen lock by user does the same as the idle screen lock after time.
Steam is installed as native package
Screen is switching off, with key or mouse movement they jump on again and show the password screen for the user for just one second. Then the GDM login with username kicks over it.
Possible log lines
messages
[ 5308.198038] traps: gnome-shell[2147] trap int3 ip:7fb1126e60ef sp:7ffc0ca41310 error:0 in libglib-2.0.so.0.8000.0[620ef,7fb1126a2000+a0000]
[ 5308.280286] rfkill: input handler enabled
[ 5309.315841] rfkill: input handler disabled
[ 5323.401424] ecryptfs_get_tree: kern_path() failed
[ 5323.401477] Reading sb failed; rc = [-2]
[ 5323.532602] ecryptfs_get_tree: kern_path() failed
[ 5323.532654] Reading sb failed; rc = [-2]
[ 5323.811278] rfkill: input handler enabled
[ 5324.429983] rfkill: input handler disabled
syslog
2025-11-26T17:20:16.280422+01:00 athena gnome-shell[14357]: Registering session with GDM
2025-11-26T17:20:16.281510+01:00 athena gnome-shell[13628]: Connection to xwayland lost
2025-11-26T17:20:16.281615+01:00 athena gnome-shell[13628]: Xwayland terminated, exiting since it was mandatory
2025-11-26T17:20:16.281649+01:00 athena gnome-shell[13628]: JS ERROR: Gio.IOErrorEnum: Xwayland exited unexpectedly#012@resource:///org/gnome/shell/ui/init.js:21:20
2025-11-26T17:20:16.281970+01:00 athena gnome-shell[13628]: Execution of main.js threw exception: Module resource:///org/gnome/shell/ui/init.js threw an exception
2025-11-26T17:20:16.298204+01:00 athena systemd[1]: session-c2.scope: Deactivated successfully.
2025-11-26T17:20:16.298354+01:00 athena systemd[1]: session-c2.scope: Consumed 2.137s CPU time.
2025-11-26T17:20:16.315666+01:00 athena gnome-shell[14357]: Launching DING process
2025-11-26T17:20:16.383293+01:00 athena gdm3: Gdm: Child process -13591 was already dead.
2025-11-26T17:20:16.384139+01:00 athena gdm3: Gdm: on_display_removed: assertion 'GDM_IS_REMOTE_DISPLAY (display)' failed
2025-11-26T17:20:16.405512+01:00 athena dbus-daemon[14170]: [session uid=1000 pid=14170] Activating service name='org.gnome.Nautilus' requested by ':1.99' (uid=1000 pid=15119 comm="gjs /usr/share/gnome-shell/extensions/zorin-deskto")
Possible Ubuntu LTS candidate Bug #2034619 “[amdgpu] gnome-shell gets SIGKILL'd when lock scre...” : Bugs : mutter package : Ubuntu
I have the same/similar problem. Screen lock occasionally crashes the desktop. I don't think its steam related (maybe?) because it has happened to me without steam running. I think it is more related to screen lock or graphics drivers. Also, screen lock doesn't put monitors to sleep. It just turns the displays black. My solution has been to set "Screen Blank" in power settings to Never and just turn the monitors off when I am away from my computer. One of the many annoyances to this otherwise wonderful OS. Not using Wayland.
Not trying to hijack your thread. Just thought this might be relevant.
I have screen blank set to 5 minutes and auto screen lock set to off. Never had a problem.
Is it installed from the System Repos or downloaded from the Steam Website?
Might be worth a Try.
Have the "Steam Installer" from software center, it did fetch some packaging from steam as i remember that.
Yes setting blank screen to off functions here also, it's a suitable workaround until Ubuntu has reworked that.