I found this issue today while upgrading my Ubuntu desktop from 14.10 to 15.04. The upgrade went by smoothly, until I rebooted and X failed to start with the dreaded error message: “The system is running in low-graphics mode”. I currently have a NVIDIA GeForce GTS 450, which is using the nvidia-304 driver. After digging around, I found that the x.org file had been delete(?), so I took the following steps to recover.
- Assuming you cannot login to GUI, choose either the console terminal from the presented options, or drop to the terminal with (control)+(alt)+(f1)
- Ensure the latest driver is installed. You will need to reboot if this is required.
$ sudo apt-get install nvidia-current
- Install the tool “nvidia-settings”. This will create the x.org file.
$ sudo apt-get install nvidia-settings
- Run the nvidia-settings command and restart.
$ sudo nvidia-settings
$ sudo shutdown -r
- Change permission of .Xauthority. This might not be required, but in my case, the .Xauthority in my user directory became owned by root, so this needed to corrected.
$ sudo chmod $USER:USER ~/.Xauthority
Now back to playing some TF2 🙂