Hello I've recently upgraded from 13.04 to 13.10 64bit.

I'm running AMD graphics with the proprietary drivers.

I have two user accounts. Mine(administrator) and my girlfriend's(standard)

My girlfriend clicks "switch user" from my lock screen and logs in fine.

I then try to click "switch user" from her lock screen and everything goes black. Then the monitor blinks on and off with just a single cursor. I have no way to access the terminal, the system is unresponsive and I have to hit the power button. Even ctrl + alt + f4 or ctrl + alt + t doesn't get me a terminal. When I press the power button on my system, it does start printing out the shutdown sequence on the monitor.

Here is my .xsession-errors

Script for ibus started at run_im.
Script for auto started at run_im.
Script for default started at run_im.

Here is hers:

init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd main process ended, respawning
init: at-spi2-registryd respawning too fast, stopped
init: logrotate main process (4726) killed by TERM signal
init: upstart-dbus-session-bridge main process (4865) terminated with status 1
init: gnome-settings-daemon main process (4843) terminated with status 1
init: gnome-session main process (4852) terminated with status 1
init: unity-panel-service main process (4863) killed by KILL signal

I found some advice in a forum to look for at-spi2-registryd in my system logs. Perhaps it will be useful.

executing this: sudo grep -r at-spi2-registryd /var/log/* produces this:

/var/log/lightdm/x-1-greeter.log:** (at-spi2-registryd:4384): WARNING **: Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files
/var/log/lightdm/x-1-greeter.log:** (at-spi2-registryd:4384): WARNING **: Unable to register client with session manager
/var/log/lightdm/x-2-greeter.log.old:** (at-spi2-registryd:7447): WARNING **: Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files
/var/log/lightdm/x-2-greeter.log.old:** (at-spi2-registryd:7447): WARNING **: Unable to register client with session manager
/var/log/lightdm/x-0-greeter.log:** (at-spi2-registryd:1378): WARNING **: Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files
/var/log/lightdm/x-0-greeter.log:** (at-spi2-registryd:1378): WARNING **: Unable to register client with session manager
/var/log/lightdm/x-0-greeter.log.old:** (at-spi2-registryd:1357): WARNING **: Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files
/var/log/lightdm/x-0-greeter.log.old:** (at-spi2-registryd:1357): WARNING **: Unable to register client with session manager

Any ideas what is going on?