Ошибка при загрузке & ldquo; Broken pipe & rdquo;

Когда я перезагружаю свой компьютер, появляется черный экран со следующим сообщением:

could not write bytes: Broken pipe

* Stopping save kernel messages...                               [ok]
* Checking battery state...                                      [ok]
* Stopping system V run level compatibility...                   [ok] 

Это уже третий раз, когда я переформатировал свой компьютер и переустановил Xubuntu из-за той же ошибки.

Ниже приведен файл журнала из "/var/log/lightdm/lightdm.log" при выполнении инструкций @sameetandpotatoes, приведенных ниже:

[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.2.3, UID=0 PID=1033
[+0.00s] DEBUG: Loaded configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Adding default seat
[+0.00s] DEBUG: Starting seat
[+0.00s] DEBUG: Starting new display for greeter
[+0.00s] DEBUG: Starting local X display
[+0.00s] DEBUG: Using VT 7
[+0.00s] DEBUG: Activating VT 7
[+0.00s] DEBUG: Logging to /var/log/lightdm/x-0.log
[+0.02s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0
[+0.02s] DEBUG: Launching X Server
[+0.02s] DEBUG: Launching process 1041: /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.02s] DEBUG: Waiting for ready signal from X server :0
[+0.04s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.04s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+1.20s] DEBUG: Got signal 10 from process 1041
[+1.20s] DEBUG: Got signal from X server :0
[+1.20s] DEBUG: Connecting to XServer :0
[+1.20s] DEBUG: Starting greeter
[+1.20s] DEBUG: Started session 1051 with service 'lightdm', username 'lightdm'
[+1.52s] DEBUG: Session 1051 authentication complete with return value 0: Success
[+1.52s] DEBUG: Greeter authorized
[+1.52s] DEBUG: Logging to /var/log/lightdm/x-0-greeter.log
[+1.52s] DEBUG: Session 1051 running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/lightdm-gtk-greeter
[+1.73s] DEBUG: Greeter closed communication channel
[+1.73s] DEBUG: Session 1051 exited with return value 1
[+1.73s] DEBUG: Greeter quit
[+1.73s] DEBUG: Failed to start greeter
[+1.73s] DEBUG: Stopping display
[+1.73s] DEBUG: Sending signal 15 to process 1041
[+1.76s] DEBUG: Process 1041 exited with return value 0
[+1.76s] DEBUG: X server stopped
[+1.76s] DEBUG: Removing X server authority /var/run/lightdm/root/:0
[+1.76s] DEBUG: Releasing VT 7
[+1.76s] DEBUG: Display server stopped
[+1.76s] DEBUG: Display stopped
[+1.76s] DEBUG: Stopping X local seat, failed to start a display
[+1.76s] DEBUG: Stopping seat
[+1.76s] DEBUG: Seat stopped
[+1.76s] DEBUG: Required seat has stopped
[+1.76s] DEBUG: Stopping display manager
[+1.76s] DEBUG: Display manager stopped
[+1.76s] DEBUG: Stopping daemon
[+1.77s] DEBUG: Exiting with return value 1