virtualbox - Unity hangs at login after upgrade to 15.04

This appears to be an issue for many. None of the suggested soloutions have worked for me:

cant-login-to-ubuntu-14-04-after-upgrade

• The permissions and state of .Xauthority & .ICEauthority are fine. Home dir is good, /tmp is as it should be.

unity-doesnt-load-no-launcher-no-dash-appears

• Setting the Ubuntu Unity plugin in ccsm did not have any effect.

I am running a provisioned VM from Oracle VBox.

It appears that the XServer isn't loading opengl:

glxinfo
name of display: :0.0
Segmentation fault (core dumped)

The syslog is throwing errors but, not sure why glx is not found:

Jul 29 13:13:21  systemd[1]: Started Session c31 of user .
Jul 29 13:13:21  systemd[1]: Starting Session c31 of user .
Jul 29 13:13:22  org.a11y.Bus[15795]: Activating service name='org.a11y.atspi.Registry'
Jul 29 13:13:22  org.a11y.Bus[15795]: Successfully activated service 'org.a11y.atspi.Registry'
Jul 29 13:13:22  org.a11y.atspi.Registry[15843]: SpiRegistry daemon is running with well-known name - org.a11y.atspi.Registry
Jul 29 13:13:22  gnome-session[15915]: Xlib:  extension "GLX" missing on display ":0".
Jul 29 13:13:22  gnome-session[15915]: message repeated 2 times: [ Xlib:  extension "GLX" missing on display ":0".]
Jul 29 13:13:22  gnome-session[15915]: gnome-session-is-accelerated: No hardware 3D support.
Jul 29 13:13:22  gnome-session[15915]: Xlib:  extension "GLX" missing on display ":0".

Jul 29 13:13:22  gnome-session[15915]: gnome-session-check-accelerated: Helper exited with code 256
Jul 29 13:13:22  gnome-session[15915]: CRITICAL: We failed, but the fail whale is dead. Sorry....

Jul 29 13:13:22  gnome-session[15915]: gnome-session[15915]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Jul 29 13:13:22  org.gnome.ScreenSaver[15795]: ** (gnome-screensaver:16003): WARNING **: Unable to get session bus: Failed to connect to socket /tmp/dbus-iYL1eZW4MO: Connection refused

Jul 29 13:13:22  org.gnome.ScreenSaver[15795]: ** (gnome-screensaver:16003): WARNING **: failed to register with the message bus

Jul 29 13:13:23  lightdm[1271]: /etc/modprobe.d is not a file
Jul 29 13:13:23  lightdm[1271]: message repeated 3 times: [ /etc/modprobe.d is not a file]

Jul 29 13:13:23  lightdm[1271]: update-alternatives: error: no alternatives for x86_64-linux-gnu_gfxcore_conf
Jul 29 13:13:23  systemd[1]: Started Session c32 of user lightdm.
Jul 29 13:13:23  systemd[1]: Starting Session c32 of user lightdm.
Jul 29 13:13:23  org.a11y.atspi.Registry[16137]: SpiRegistry daemon is running with well-known name - org.a11y.atspi.Registry

All this is telling me is that the whale is dead.

lcpci is finding my graphics card:

00:02.0 VGA compatible controller: InnoTek Systemberatung GmbH VirtualBox Graphics Adapter

Additionally, setting the display manager to gdm bricks it.

I can get in to the machine by logging in to GNOME Classic (MetaCity) but no other desktop will work. Except KDE.

All I had to do was post a question here. Some combination of the above worked finally. The last thing I did was:

sudo apt-get purge fglrx lightdm && sudo apt-get install lightdm ubuntu-desktop

and then

dconf reset -f /org/compiz/
setsid unity

from Unity missing? Can't see top or side panels