org.gnome.Shell.desktop[6022]: Window manager warning: Failed to parse saved session file: Datei »/var/lib/gdm/.config/mutter/sessions/101238a11fa21cfa165138963016161500000059380000.ms« konnte nicht geöffnet werden: Datei oder Verzeichnis nicht gefunden
The directory /var/lib/gdm/.config/mutter/ does not exist. And why should there be a saved session in /var/lib/gdm anyways?
arch-gnome org.gnome.Shell.desktop[778]: Window manager warning: Failed to parse saved session file: Failed to open file “/var/lib/gdm/.config/mutter/sessions/10b6742ca1fbaae9ef16513912756950900000007700000.ms”: No such file or directory
It looks like a script check command that does not send errors to /dev/null.
I assume it’s not Gnome provided, probably some EnOS script for gnome?
Maybe check your autostart applications and local ~/.config/autostart/.
Gnome maintainer??