I am trying to upgrade my system from Ubuntu 12.04 to 14.04. Everything installs well but the desktop appears blank. I have enabled Ubuntu Unity program after going into CCSM, rebooted the system but still the same blank desktop. After that I tried to do sudo apt-get install gnome and rebooted, logged in using Gnome Classic (Gnome DE) but nothing differed. In the kernel log, it comes up with the following error:

fglrx: module verification failed: signature and/or required key missing -tainting kernel
*ERROR* No supported display adapters were found
*ERROR* firegl_init_devices failed

Can anyone direct me to a solution?

  • The top panel does appear at this point, I did re check in CCSM if the unity plugin is enabled which it was, any suggestions? At this point my desktop is restored with all the folders and files that existed before Oct 23, 2014 at 20:47

2 Answers 2


Try this (from Gede Suartana's blog).

Once you are booted up to the blank desktop... press CTRL + ALT + F1.

apt-get install --reinstall ubuntu-desktop
apt-get install unity
apt-get purge nvidia* bumblebee*
apt-get install nvidia-prime

shutdown -r now

Hope this helps!


Try switching the terminal (CTRL+ALT+F1) and then remove the configuration file ~/.config/dconf/user like this :

(this action will remove your gnome 3 settings)

sudo service lightdm stop
rm ~/.config/dconf/user
sudo service lightdm start
  • thanks a lot! this helped me resetting display troubles on Ubuntu 14.04 (there was a persisting dummy monitor impossible to remove, even after resetting lots of display settings)
    – Anybug
    Jan 17, 2019 at 16:13

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