Update on Ubuntu - coloured lines around everything [duplicate]

Solution 1:

This is a bug with unofficial Nvidia drivers that you installed from a PPA.

The 375-378 drivers my be recommended by Nvidia at their site, but they are not tested for Ubuntu and not recommended by Canonical.

Run in a terminal

sudo apt install ppa-purge
sudo ppa-purge ppa:graphics-drivers/ppa
sudo apt update
sudo apt install nvidia-367

and reboot.