Hardware
External monitor is not detected
A second screen that stays blank. Test input, cable and port in that order — one of the three is almost always the answer.
Read before you start
Do not force a connector or use a bent adapter. A damaged HDMI or USB-C port is a board-level repair, so test the cable on another device first.
This guide is for you if
- Second screen stays blank
- Display not listed in settings
- Works on another laptop but not this one
Step by step
Work top to bottom0 of 5 steps done
Select the input manually
Use the monitor's buttons to choose the input that matches the cable you plugged in. Auto-detect fails more often than people expect.
Swap the cable and the adapter
Try a different cable, then a different port on the laptop. USB-C docks and mini-DisplayPort adapters are a common failure point.
Some cheap USB-C adapters are video-only — check the resolution and refresh rate they support.
Force a redetect
Windows: Windows key + P → Duplicate or Extend, then Settings → Display → Detect. macOS: System Settings → Displays, hold Option to reveal 'Detect Displays'.
Update the graphics driver
Install the driver from the GPU vendor directly — Intel, AMD or NVIDIA — rather than relying on the Windows update version, then reboot and test.
Test the monitor on another machine
Plug it into another computer or TV box. If it works there, the laptop output is the fault; if not, the monitor or its cable is.