Don't be careful the update, the system from Ubuntu16 update to 18, and then start lightdm when unable to start
As shown in figure
After via sudo DPKG -- reconfigure gdm3 command chose lightdm
After the restart the system automatically enters the devices tty1, sudo apt install ubuntu desktop - tried useless, sudo systemctl set - the default graphical. The target is useless,
Situation now is lightdm could not be opened, the system automatically enters the devices tty1, there are a great god know what to do?

CodePudding user response:

X service startup failed, reinstall the X Window System