Laptop External Display Troubleshooting

When you are testing the DisplayPort/HDMI on a laptop, and the Display option in Settings Manager is not allowing you to select the external monitor, try the following:

After plugging the laptop into the external monitor, open terminal and enter

Depending on your system, LVDS will be either 0 or 1, and DisplayPort (DP) and HDMI could also be 0 or 1. If your system has multiple DisplayPort or HDMI options, the computer will note which one has the external monitor plugged in; that's the number you want. After than, copy/paste the following code into terminal:

If you have an HDMI port, change DP to HDMI. Change the numbers next to DP and LVDS to the ones used with your system. Hit enter, and an option will pop up, select the left monitor. Hit enter again. The external screen should now show the laptop screen.