tl;dr – Upgrading Ubuntu 12.04 to 14.04 is/was a nightmare. Seriously, just reinstall everything rather than upgrade. Backup your system before screwing around with it.

My periodic urge to screw around with my computer had surfaced yet again, this time in the form of updating Ubuntu 12.04 to 14.04. I had finally gotten my hands on a freakin’ amazing internet connection, thanks to the place I worked over the summer and saw it as a golden opportunity to download me a fresh 3GB cup o’ Ubuntu. Having abandoned Windows 3 years ago, I felt confident enough to handle any disaster coming my way.

I used this and this as reference.

So opened up my Terminal and I started the update process by $ nano /etc/update-manager/release-upgrades And checking if Prompt=lts.

Then going all:

$ sudo apt-get install update-manager-core
$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo do-release-upgrade

You may have noticed that I didn’t bother backing up my system, thinking “Haha, what’s the worst that could happen?”. This point will be important in a moment.

In the beginning, everything was going as expected, with prompts appearing, me entering stuff et al. After a while though, all hell broke lose.

All my running applications crashed, and my terminal window became unresponsive. I hedged a guess that X-server must’ve crashed. I waited 5, 10, 15 minutes for something to happen, but nothing did. So I did the only thing I could do at that point.

I force-shutdown my computer by pressing the power button. Then turned it back on.

I was greeted by the GRUB menu having the ‘Restore Ubuntu 12.04 to Factory Settings’, ‘Ubuntu, with Linux 3.2.0-24-generic (recovery mode), and two ‘Memory test’ options. No regular Ubuntu 12.04 bootup option.

I now regretted being too ballsy for my own good and not taking a backup. Shit.

Then began a panic-stricken search on Google and of course, Stack Overflow. Finally found this life-saver of an answer.

If you’ve reached here through a similar panic-stricken Google search, you’re welcome.

I ended up going through Step 3, after selecting the Recovery Mode option on GRUB, then dropping down to root shell prompt:

# dpkg-reconfigure -a
# apt-get upgrade
# apt-get dist-upgrade
# reboot

After reboot, I almost gave a squeal of joy after seeing the pleasant pastel-violet background of the Ubuntu login screen. But my happiness was not meant to be.

I could login into my account, even after multiple attempts. It just showed, ‘Failed to start session’, like here.

A part of me actually thought that this was karma paying me back for stealing internet from my workplace. Never.again.

Fortunately, this was relatively easy to fix, after following this thread.

I got into the command line from the login page through Alt+Ctrl+F2 and typed:

$ sudo su
# apt-get upgrade
# apt-get install --reinstall ubuntu-desktop
# apt-get install unity
# apt-get install lightdm
# reboot

And stuff finally started working after that.

I finally switched to Arch Linux, a rolling-release distro after this fiasco took place, and have never been happier. I also paid dearly for not backing up my files. Again.