Likely fix
Fix: Second monitor not detected
A second monitor is usually not detected because of the wrong input source, loose cable, bad adapter, display settings, graphics driver issue, or a port that does not output video.
Quick answer
Set the monitor to the correct input, reconnect the cable, then open display settings and choose Detect. If using USB-C or an adapter, confirm the port and adapter support video.
Important warning
Some USB-C ports are charge-only or data-only and cannot run a monitor.
Try this
- 1 Make sure the second monitor is powered on.
- 2 Set the monitor to the correct input source.
- 3 Reconnect the cable at both ends.
- 4 Restart the computer with the second monitor connected.
- 5 Open display settings and choose Detect.
- 6 Try Duplicate or Extend display mode.
- 7 Try another cable, port, or adapter.
- 8 Update graphics drivers if the monitor is still not detected.
Common causes
Monitor is on the wrong input source.
Display mode is set to show only one screen.
Cable or adapter is bad.
USB-C port does not support video.
Graphics driver needs an update.
Dock or hub does not support multiple displays.
What to check next
- Check whether the monitor works as the only monitor.
- Check display settings for Duplicate, Extend, or Show only.
- Check whether the cable works with another screen.
- Check whether the adapter supports your monitor.
- Check whether the dock supports multiple monitors.
This might need a cable or adapter
If this fix points to a cable issue, check the related cable guide before buying the wrong one.
Check the related cable →