Xubuntu session doesn't assign groups, logout brings me back to desktop

The system boots up normally, and I log in. I open an xterm and this happens: $ groups rphelps $ su rphelps Password: $ groups rphelps adm cdrom sudo dip www-data plugdev lpadmin sambashare kismet docker If I log in via SSH, my groups are set correctly. If I log into a tty instead of X, my groups are set correctly. When I try to log out of the X session or hit Ctrl+Alt+L, it closes the session, but then it seems like the greeter can't be (re)started, or the lockscreen doesn't work, and *it brings me back to my desktop*. I was recently mucking around with screen savers (xscreensaver, gnome-screensaver, etc.) trying to get the screen to lock after 30 minutes (no luck). Did purging those have remove something vital for logging out? I haven't modified any /etc/ files manually. Xubuntu 18.04 Edit 1: $ journalctl -u lightdm.service -- Reboot -- Jul 25 11:21:01 rphelps-DELL systemd: Starting Light Display Manager... Jul 25 11:21:01 rphelps-DELL lightdm: Seat type 'xlocal' is deprecated, use 'type=local' instead Jul 25 11:21:01 rphelps-DELL systemd: Started Light Display Manager. Jul 25 11:21:02 rphelps-DELL lightdm: pam_kwallet(lightdm-greeter:setcred): (null): pam_sm_setcred Jul 25 11:21:02 rphelps-DELL lightdm: pam_kwallet5(lightdm-greeter:setcred): (null): pam_sm_setcred Jul 25 11:21:02 rphelps-DELL lightdm: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0) Jul 25 11:21:03 rphelps-DELL lightdm: pam_kwallet(lightdm-greeter:session): (null): pam_sm_open_session Jul 25 11:21:03 rphelps-DELL lightdm: pam_kwallet(lightdm-greeter:session): pam_kwallet: open_session called without kwallet_key Jul 25 11:21:03 rphelps-DELL lightdm: pam_kwallet5(lightdm-greeter:session): (null): pam_sm_open_session Jul 25 11:21:03 rphelps-DELL lightdm: pam_kwallet5(lightdm-greeter:session): pam_kwallet5: open_session called without kwallet5_key Jul 25 11:21:03 rphelps-DELL lightdm: pam_succeed_if(lightdm:auth): incomplete condition detected Jul 25 11:22:37 rphelps-DELL lightdm: pam_kwallet(lightdm:auth): (null): pam_sm_authenticate Jul 25 11:22:37 rphelps-DELL lightdm: pam_kwallet5(lightdm:auth): (null): pam_sm_authenticate Jul 25 11:22:37 rphelps-DELL lightdm: pam_kwallet(lightdm:setcred): pam_kwallet: pam_sm_setcred Jul 25 11:22:37 rphelps-DELL lightdm: pam_kwallet5(lightdm:setcred): pam_kwallet5: pam_sm_setcred Jul 25 11:22:37 rphelps-DELL lightdm: pam_unix(lightdm:session): session opened for user rphelps by (uid=0) Jul 25 11:22:37 rphelps-DELL lightdm: pam_kwallet(lightdm:session): pam_kwallet: pam_sm_open_session Jul 25 11:22:37 rphelps-DELL lightdm: Error writing to daemon: Bad file descriptor Jul 25 11:22:37 rphelps-DELL lightdm: Failed to write utmpx: Permission denied Jul 25 11:34:02 rphelps-DELL lightdm: Failed to write utmpx: Permission denied Jul 25 11:34:02 rphelps-DELL lightdm: Error writing to daemon: Bad file descriptor Jul 25 11:34:02 rphelps-DELL lightdm: Failed to write utmpx: Permission denied Jul 25 11:40:38 rphelps-DELL lightdm: Failed to write utmpx: Permission denied Jul 25 11:40:38 rphelps-DELL lightdm: Error writing to daemon: Bad file descriptor Jul 25 11:40:38 rphelps-DELL lightdm: Failed to write utmpx: Permission denied Jul 25 11:50:05 rphelps-DELL lightdm: Failed to write utmpx: Permission denied Jul 25 11:50:05 rphelps-DELL systemd: Stopping Light Display Manager... Jul 25 11:50:05 rphelps-DELL lightdm: Error updating user /org/freedesktop/Accounts/User1000: GDBus.Error:org.freedesktop.systemd1.ShuttingDown: Refusing Jul 25 11:50:05 rphelps-DELL lightdm: seat_lock: assertion 'seat != NULL' failed Jul 25 11:50:05 rphelps-DELL lightdm: Error updating user /org/freedesktop/Accounts/User1000: GDBus.Error:org.freedesktop.systemd1.ShuttingDown: Refusing Jul 25 11:50:05 rphelps-DELL lightdm: Error updating user /org/freedesktop/Accounts/User1000: GDBus.Error:org.freedesktop.systemd1.ShuttingDown: Refusing Jul 25 11:50:07 rphelps-DELL systemd: Stopped Light Display Manager.