I wanted to replace Bumblebee with Nvidia Prime for more performance. I used these commands:
sudo apt-get purge libvdpau-va-gl1 bumblebee* nvidia* sudo apt-get install nvidia-331 nvidia-settings nvidia-prime
Then i rebooted. At first everything looked fine. Nvidia drivers was enabled with perfect graphic performance. Then I tried to use power saving mode(Intel card) from Nvidia Settings. It said i have to log out and log in. I did as it said and then, Unity was gone. No launcher, no top bar, no folders and shourtcuts nothing but my wallpaper and cursor. Right clicking or Ctrl + Alt + T didn't work either. I could get unity back when I reinstalled drivers and Prime with commands I gave above. I tried to reinstall Bumblebee, get back to Nouveau drivers, using different versions of drivers but none of them helped. I don't want to reinstall my system just because of this so can anyone help me about this? How can i use Prime properly or at least get back to Bumblebee?