On update, ubuntu shows 2 screen as default.
Here is fix
xrandr | grep connected
sudo nano /etc/lightdm/monitor1-off.sh
#!/bin/bash xrandr --output HDMI1 --off #change HDMI1 with your device id ( you can check by executing command 'xrandr'
sudo chmod +x /etc/lightdm/monitor1-off.sh
Edit /etc/lightdm/lightdm.conf and add the following line to the file
It will remove 2nd screen on OS starting.