Невозможно войти. Как отладить?

Мне пришлось перезагрузить систему кнопкой перезагрузки. После перезагрузки я не могу войти. Когда я ввожу свой пароль, похоже, X-сервер просто перезагружается.

Я могу войти как гость, а также я могу войти в текстовом режиме TTY. Вот первые 150 строк моего lightdm.log:

[+0.04s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.04s] DEBUG: Starting Light Display Manager 1.2.1, UID=0 PID=1070
[+0.04s] DEBUG: Loaded configuration from /etc/lightdm/lightdm.conf
[+0.04s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.04s] DEBUG: Registered seat module xlocal
[+0.04s] DEBUG: Registered seat module xremote
[+0.04s] DEBUG: Adding default seat
[+0.04s] DEBUG: Starting seat
[+0.04s] DEBUG: Starting new display for automatic login as user dmytro
[+0.04s] DEBUG: Starting local X display
[+3.64s] DEBUG: X server :0 will replace Plymouth
[+3.66s] DEBUG: Using VT 7
[+3.66s] DEBUG: Activating VT 7
[+3.66s] DEBUG: Logging to /var/log/lightdm/x-0.log
[+3.66s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0
[+3.66s] DEBUG: Launching X Server
[+3.66s] DEBUG: Launching process 1154: /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch -background none
[+3.66s] DEBUG: Waiting for ready signal from X server :0
[+3.66s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+3.66s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+10.78s] DEBUG: Got signal 10 from process 1154
[+10.78s] DEBUG: Got signal from X server :0
[+10.78s] DEBUG: Stopping Plymouth, X server is ready
[+10.80s] DEBUG: Connecting to XServer :0
[+10.80s] DEBUG: Automatically logging in user dmytro
[+10.80s] DEBUG: Started session 1303 with service 'lightdm-autologin', username 'dmytro'
[+13.22s] DEBUG: Session 1303 authentication complete with return value 0: Success
[+13.26s] DEBUG: Autologin user dmytro authorized
[+13.27s] DEBUG: Autologin using session ubuntu
[+14.44s] DEBUG: Dropping privileges to uid 1000
[+14.48s] DEBUG: Restoring privileges
[+14.49s] DEBUG: Dropping privileges to uid 1000
[+14.49s] DEBUG: Writing /home/dmytro/.dmrc
[+14.61s] DEBUG: Restoring privileges
[+14.81s] DEBUG: Starting session ubuntu as user dmytro
[+14.81s] DEBUG: Session 1303 running command /usr/sbin/lightdm-session gnome-session --session=ubuntu
[+15.76s] DEBUG: New display ready, switching to it
[+15.76s] DEBUG: Activating VT 7
[+15.76s] DEBUG: Registering session with bus path /org/freedesktop/DisplayManager/Session0
[+16.63s] DEBUG: Session 1303 exited with return value 0
[+16.63s] DEBUG: User session quit
[+16.63s] DEBUG: Stopping display
[+16.63s] DEBUG: Sending signal 15 to process 1154
[+17.19s] DEBUG: Process 1154 exited with return value 0
[+17.19s] DEBUG: X server stopped
[+17.19s] DEBUG: Removing X server authority /var/run/lightdm/root/:0
[+17.19s] DEBUG: Releasing VT 7
[+17.19s] DEBUG: Display server stopped
[+17.19s] DEBUG: Display stopped
[+17.19s] DEBUG: Active display stopped, switching to greeter
[+17.19s] DEBUG: Switching to greeter
[+17.19s] DEBUG: Starting new display for greeter
[+17.19s] DEBUG: Starting local X display
[+17.19s] DEBUG: Using VT 7
[+17.19s] DEBUG: Logging to /var/log/lightdm/x-0.log
[+17.19s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0
[+17.19s] DEBUG: Launching X Server
[+17.19s] DEBUG: Launching process 1563: /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+17.19s] DEBUG: Waiting for ready signal from X server :0
[+17.48s] DEBUG: Got signal 10 from process 1563
[+17.48s] DEBUG: Got signal from X server :0
[+17.48s] DEBUG: Connecting to XServer :0
[+17.48s] DEBUG: Starting greeter
[+17.48s] DEBUG: Started session 1575 with service 'lightdm', username 'lightdm'
[+17.61s] DEBUG: Session 1575 authentication complete with return value 0: Success
[+17.61s] DEBUG: Greeter authorized
[+17.61s] DEBUG: Logging to /var/log/lightdm/x-0-greeter.log
[+17.68s] DEBUG: Session 1575 running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/unity-greeter
[+20.86s] DEBUG: Greeter connected version=1.2.1
[+20.86s] DEBUG: Greeter connected, display is ready
[+20.86s] DEBUG: New display ready, switching to it
[+20.86s] DEBUG: Activating VT 7
[+20.86s] DEBUG: Stopping greeter display being switched from
[+24.90s] DEBUG: Greeter start authentication for dmytro
[+24.90s] DEBUG: Started session 1746 with service 'lightdm', username 'dmytro'
[+25.10s] DEBUG: Session 1746 got 1 message(s) from PAM
[+25.10s] DEBUG: Prompt greeter with 1 message(s)
[+31.87s] DEBUG: Continue authentication
[+33.75s] DEBUG: Session 1746 authentication complete with return value 7: Authentication failure
[+33.75s] DEBUG: Authenticate result for user dmytro: Authentication failure
[+33.75s] DEBUG: Greeter start authentication for dmytro
[+33.75s] DEBUG: Session 1746: Sending SIGTERM
[+33.75s] DEBUG: Started session 2264 with service 'lightdm', username 'dmytro'
[+33.75s] DEBUG: Session 2264 got 1 message(s) from PAM
[+33.75s] DEBUG: Prompt greeter with 1 message(s)
[+36.41s] DEBUG: Continue authentication
[+36.53s] DEBUG: Session 2264 authentication complete with return value 0: Success
[+36.53s] DEBUG: Authenticate result for user dmytro: Success
[+36.54s] DEBUG: User dmytro authorized
[+36.54s] DEBUG: Greeter requests session ubuntu
[+36.54s] DEBUG: Using session ubuntu
[+36.54s] DEBUG: Stopping greeter
[+36.54s] DEBUG: Session 1575: Sending SIGTERM
[+37.41s] DEBUG: Greeter closed communication channel
[+37.41s] DEBUG: Session 1575 exited with return value 0
[+37.41s] DEBUG: Greeter quit
[+37.42s] DEBUG: Dropping privileges to uid 1000
[+37.42s] DEBUG: Restoring privileges
[+37.43s] DEBUG: Dropping privileges to uid 1000
[+37.43s] DEBUG: Writing /home/dmytro/.dmrc
[+38.35s] DEBUG: Restoring privileges
[+40.37s] DEBUG: Starting session ubuntu as user dmytro
[+40.37s] DEBUG: Session 2264 running command /usr/sbin/lightdm-session gnome-session --session=ubuntu
[+40.39s] DEBUG: Registering session with bus path /org/freedesktop/DisplayManager/Session1
[+50.78s] DEBUG: Session 2264 exited with return value 0
[+50.78s] DEBUG: User session quit
[+50.78s] DEBUG: Stopping display
[+50.78s] DEBUG: Sending signal 15 to process 1563
[+51.53s] DEBUG: Process 1563 exited with return value 0
[+51.53s] DEBUG: X server stopped
[+51.53s] DEBUG: Removing X server authority /var/run/lightdm/root/:0
[+51.53s] DEBUG: Releasing VT 7
[+51.53s] DEBUG: Display server stopped
[+51.53s] DEBUG: Display stopped
[+51.53s] DEBUG: Active display stopped, switching to greeter
[+51.53s] DEBUG: Switching to greeter
[+51.53s] DEBUG: Starting new display for greeter
[+51.53s] DEBUG: Starting local X display
[+51.53s] DEBUG: Using VT 7
[+51.53s] DEBUG: Logging to /var/log/lightdm/x-0.log
[+51.53s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0
[+51.53s] DEBUG: Launching X Server
[+51.53s] DEBUG: Launching process 2894: /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+51.53s] DEBUG: Waiting for ready signal from X server :0
[+51.75s] DEBUG: Got signal 10 from process 2894
[+51.75s] DEBUG: Got signal from X server :0
[+51.75s] DEBUG: Connecting to XServer :0
[+51.75s] DEBUG: Starting greeter
[+51.75s] DEBUG: Started session 2898 with service 'lightdm', username 'lightdm'
[+51.76s] DEBUG: Session 2898 authentication complete with return value 0: Success
[+51.76s] DEBUG: Greeter authorized
[+51.76s] DEBUG: Logging to /var/log/lightdm/x-0-greeter.log
[+51.76s] DEBUG: Session 2898 running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/unity-greeter
[+53.26s] DEBUG: Greeter connected version=1.2.1
[+53.26s] DEBUG: Greeter connected, display is ready
[+53.26s] DEBUG: New display ready, switching to it
[+53.26s] DEBUG: Activating VT 7
[+53.26s] DEBUG: Stopping greeter display being switched from
[+54.17s] DEBUG: Greeter start authentication for dmytro
[+54.17s] DEBUG: Started session 3152 with service 'lightdm', username 'dmytro'
[+54.18s] DEBUG: Session 3152 got 1 message(s) from PAM
[+54.18s] DEBUG: Prompt greeter with 1 message(s)
[+58.61s] DEBUG: Continue authentication
[+58.65s] DEBUG: Session 3152 authentication complete with return value 0: Success
[+58.65s] DEBUG: Authenticate result for user dmytro: Success
[+58.66s] DEBUG: User dmytro authorized
[+58.66s] DEBUG: Greeter requests session ubuntu
[+58.66s] DEBUG: Using session ubuntu
[+58.66s] DEBUG: Stopping greeter
[+58.66s] DEBUG: Session 2898: Sending SIGTERM

Как я могу это исправить? Какие другие файлы.log могут дать мне подсказку?

Обновление: возможно, это дублирует вход в систему Desktop, терминал работает