Situation: I have upgraded two Nvidia Optimus laptops from Linux Mint 17.3 to version 18.Problem: After upgrade, Nvidia Optimus does not work, both laptops booted into Cinnamon fallback mode.Temporary solution: I changed the graphics driver to Nouveau, then the Cinnamon works, but there is an X icon in system tray indicating Active graphics card: Unknown. And I obviously need a real solution.
Active graphics card Unknown after upgrade to Linux Mint 18
linux mint;upgrade;nvidia;optimus
Solution: sudo apt-get purge bumblebee*sudo apt-get purge bbswitch*sudo apt-get purge nvidia*sudo apt-get --purge autoremoveAfterwards, run driver-manager, install the Nvidia proprietary driver and reboot.