● lightdm.service - Light Display Manager
   Loaded: loaded (/lib/systemd/system/lightdm.service; enabled; vendor preset: enabled)
  Drop-In: /lib/systemd/system/display-manager.service.d
           └─xdiagnose.conf
   Active: active (running) since Tue 2015-06-02 09:58:08 EDT; 15min ago
     Docs: man:lightdm(1)
  Process: 3800 ExecStartPre=/bin/sh -c [ "$(basename $(cat /etc/X11/default-display-manager 2>/dev/null))" = "lightdm" ] (code=exited, status=0/SUCCESS)
 Main PID: 3804 (lightdm)
   Memory: 106.9M
   CGroup: /system.slice/lightdm.service
           ├─3804 /usr/sbin/lightdm
           └─3814 /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch

Jun 02 09:58:08 attente lightdm[3804]: Configuration file /usr/share/lightdm/lightdm.conf.d/55-unity8.conf contains a deprecated [SeatDefaults] section, use [Seat:*] instead
Jun 02 09:58:08 attente systemd[1]: Started Light Display Manager.
Jun 02 09:58:08 attente lightdm[3804]: ** (lightdm:3804): CRITICAL **: session_get_login1_session_id: assertion 'session != NULL' failed
Jun 02 09:58:08 attente lightdm[3824]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
Jun 02 09:58:08 attente lightdm[3824]: PAM adding faulty module: pam_kwallet.so
Jun 02 09:58:08 attente lightdm[3824]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Jun 02 09:58:09 attente lightdm[3896]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
Jun 02 09:58:09 attente lightdm[3896]: PAM adding faulty module: pam_kwallet.so
Jun 02 09:58:09 attente lightdm[3896]: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "william"
Jun 02 09:58:13 attente lightdm[3896]: pam_unix(lightdm:session): session opened for user william by (uid=0)