How to enable root GUI login in Ubuntu

You can not log in as the root account when you first install Ubuntu.

If you want to login as root in GUI, follow the below procedure.

1. $ sudo vi /etc/lightdm/lightdm.conf

* Even if it is not exist, there is nothing wrong.

2. Copy and paste
[SeatDefaults]
greeter-session=unity-greeter
user-session=ubuntu
greeter-show-manual-login=true

3. Save and reboot the system.

Check environment
O      S	Ubuntu 16.04(x64)	CPU	Intel i7-4710MQ 2.50GHz
SHELL	GNU bash(4.3.48)	RAM	1 GB