How do I fix "Oh no! Something has gone wrong." (gdm3 fails to start)

The machine was running Debian wheezy and was recently upgraded to Jessie. Everything has worked fine for some time. However, after a reboot today the desktop won't load.

/var/log/messages shows gnome-shell: segfault at 0 error 4 in libupower-glib.so.3.0.0

I have tried reinstalling gnome-shell, gnome-session, gdm3, and libupower to no avail.

(Sorry about the formatting, I'm on a phone.)

I have the same problem. I solved the problem by following these steps:

Reboot your system.

Press Ctrl + Alt +F4 and type startx

Open the terminal and remove gnome desktop

apt-get remove gnome-session

apt-get autoremove

I have KDE desktop installed , to reconfigure kdm i am using the following command:

sudo dpkg-reconfigure kdm

and choose kdm

Next step reboot and reinstall gnome desktop.

Interestingly enough, I found my own question when I broke my system in a similar way. I'm not sure exactly how I did it, the last thing I installed was the terminal emulator terminator but I haven't rebooted my machine for quite some time so there may have been more relevant changes that I have forgotten about.

To get out of the white screen of death I forcefully removed all the gnome packages:

dpkg -r --force-depends `dpkg --get-selections | grep gnome | cut -f 1`
dpkg -r --force-depends `dpkg --get-selections | grep deinstall | cut -f 1`

This leaves the system in a very broken state. However, I then installed gnome and many (all?) of the other dependencies:

aptitude install task-gnome-desktop

The first couple options to resolve the package conflicts involved aptitude removing most or all of the packages that had unmet dependencies. I cycled through a few other options until I got one that wasn't going to remove anything but rather just install the missing packages which was about 20 more.

The only thing that seems to still be broken is that the expand/collapse buttons for threads in Thunderbird are missing.