I have upgraded Ubuntu from 12.04 to 14.04. Afterwards, xserver couldn't start. I have downloaded the latest nvidia drivers from here and rebooted. GRUB now has the following entries:
*Ubuntu
Advanced options for Ubuntu
Memory test (memtest86+)
Memory test (memtest86+, serial console 115200)
When selecting "Advanced options for Ubuntu" the following entries are displayed:
Ubuntu, with Linux 3.13.0-34-generic
Ubuntu, with Linux 3.13.0-34-generic (recovery mode)
Ubuntu, with Linux 3.5.0-54-generic
Ubuntu, with Linux 3.5.0-54-generic (recovery mode)
Ubuntu, with Linux 3.5.0-47-generic
Ubuntu, with Linux 3.5.0-47-generic (recovery mode)
Ubuntu, with Linux 3.5.0-46-generic
Ubuntu, with Linux 3.5.0-46-generic (recovery mode)
Ubuntu, with Linux 3.5.0-44-generic
Ubuntu, with Linux 3.5.0-44-generic (recovery mode)
Ubuntu, with Linux 3.5.0-42-generic
Ubuntu, with Linux 3.5.0-42-generic (recovery mode)
Ubuntu, with Linux 3.5.0-41-generic
Ubuntu, with Linux 3.5.0-41-generic (recovery mode)
Ubuntu, with Linux 3.5.0-40-generic
Ubuntu, with Linux 3.5.0-40-generic (recovery mode)
Ubuntu, with Linux 3.5.0-23-generic
Ubuntu, with Linux 3.5.0-23-generic (recovery mode)
After, installing the drivers, however, selecting any non recovery entry would lead to a black screen with a blinking cursor. After booting into recovery mode I have deleted all nvidia drivers by running:
sudo ./usr/bin/nvidia-installer --uninstall
Now I could again boot from any kernel without GUI enabled. I've tried starting xserver from the command line by running:
startx
An error related to ~/.XAuthority has occured. Running the command again as root threw the error:
Failed to insert nvidia. No such symbol
Next, I tried reinstalling xserver:
sudo apt-get install --reinstall xorg
The command was run successfully but I'm now getting the following errors when attempting to startx:
(EE) module ABI major version (6) doesn't match the server's version (8)
xinit: connection to X server lost
waiting for X server to shut down (EE) Server terminated successfully (0). Closing log file.
Why does this occur?
Edit #1:
I have installed nvidia-current-updates:
sudo apt-get install nvidia-current-updates
and ran startx again. The output was:
xauthL: timeout in locking authority file ~/.Xauthority
Afterwards, the screen kept flashing. I had to jump into terminal mode. The output is as follows:
waiting for X server to accept connections
and a screen of lines:
No protocol specified
Edit #2:
After removing the .Xauthority file and running startx the following error is shown:
(EE) module ABI major version (6) doesn't match the server's version (8)
xinit: connection to X server lost
waiting for X server to shut down (EE) Server terminated successfully (0). Closing log file.
Best Answer
OK So you broke X, will will have to re install the system
You will need your live DVD/USB,or you have to make one.
Boot the live medium and choose install Ubuntu
If you see an option to upgrade Ubuntu 14.04 to 14.04 (or someting like this UPGRADE is the important word) (at the top) use this to re install
If not, that's OK choose something else
Highlight your current Ubuntu installation and set its mount point to /
THIS IS THE IMPORTANT BIT There is a little box that says format on the drive make sure you UNTICK this box (eg format is disabled)
Then install, this will re install all the system files (including X) but will not change your /home folder of user details.
Reboot when it is finished
Here is the documentation on this