unity - Can sign in to xfce but not to Ubuntu Desktop environment after update - Ask Ubuntu

i updated ubuntu 14.04 installation , upon rebooting no longer able sign ubuntu desktop environment. i've tried several approaches such as:

1. renaming .xauthority , restarting
2. ensuring .xauthority not owned root (also ran command sudo chown -r $user:$user $home pretty files in home directory executable)
3. sudo apt-get install ubuntu-desktop , sudo apt-get install --reinstall ubuntu-desktop

content of .xsession-errors:

script ibus started @ run_im. script auto started @ run_im. script default started @ run_im. 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: gnome-session (unity) main process (6756) terminated status 1 init: unity-settings-daemon main process (6735) killed term signal init: disconnected notified d-bus bus init: logrotate main process (6631) killed term signal init: xsession-init main process (6726) killed term signal init: unity-panel-service main process (6760) killed term signal init: upstart-dbus-session-bridge main process (6675) terminated status 1 init: hud main process (6740) killed term signal 

and contents of /var/log/lightdm/lightdm.log

update

i tried fix described here and ubuntu desktop environment gone. -- , have 3 desktop environments (including gnome) , xfce works.

latest update

i've installed loads of desktop managers(?) shown below 2 of them work. gnome flashback (metacity) , xfce session. rest don't work.

final update

because many attempt fix system made worse had install ubuntu 16.04 lts.

it looks @ point tried run xsession root , has left other files owned root in home dir.

to list files in home dir owned root

find ~ -uid 0 

have @ list , chown try again.

it might idea send file reference later in case introduce more issues later changes.

if happy files listed command should returned ownership run command.

find ~ -uid 0 -exec chown $user:$user -r {} \; 

it worth creating fresh user account comparison, try login in that, if doesn't work issue may not @ user level system thing.