diff -Naur lightdm-gtk-greeter-settings-1.2.2/lightdm_gtk_greeter_settings/helpers.py lightdm-gtk-greeter-settings-1.2.2-new/lightdm_gtk_greeter_settings/helpers.py
--- lightdm-gtk-greeter-settings-1.2.2/lightdm_gtk_greeter_settings/helpers.py	2017-09-19 13:56:17.000000000 +0300
+++ lightdm-gtk-greeter-settings-1.2.2-new/lightdm_gtk_greeter_settings/helpers.py	2022-02-06 23:09:55.230342383 +0200
@@ -188,7 +188,7 @@
         files += ['/etc/lightdm/lightdm.conf']
         config = configparser.RawConfigParser(strict=False)
         config.read(files)
-        username = config.get('LightDM', 'greeter-user', fallback='lightdm')
+        username = config.get('LightDM', 'greeter-user', fallback='gdm')
 
         pw = pwd.getpwnam(username)
         uid = pw.pw_uid