- Press Windows logo key + P and make sure Extend is selected. If it is already selected, continue.
- Disconnect the dock and all other accessories from the laptop. Connected docks, dongles, and adapters can cause conflicts.
- Connect the USB-C display device or dock directly to the laptop instead of through extra hubs or adapters. Windows guidance says USB-C display devices should be connected directly to the correct USB-C port.
- Check cable and port compatibility:
- Make sure the laptop, dock, monitor, and cable all support the same display feature such as DisplayPort, MHL, or HDMI Alternate Mode.
- Make sure the USB-C connection is plugged into the USB-C port that supports the correct Alternate Mode.
- Use the cable that came with the device if available, because not all USB-C cables support video.
- Try basic hardware isolation:
- Reseat the USB-C cable.
- Try a different USB-C cable.
- Try the monitor with another system.
- If the laptop has another video output option, test that as well.
- Restart the laptop. If the display setup was working before and suddenly stopped, try Windows logo key + Ctrl + Shift + B to reset the graphics driver, then restart if needed.
- If using more than one external monitor, confirm the laptop can actually drive two external displays. If one external monitor works but adding the second does not, the display adapter may not support more than one monitor. A display splitter will only duplicate the same signal, not extend to two independent displays.
- If the USB-C dock still is not detected, try a different USB port if available. Windows also shows Use different USB port when the current USB-C port has limited functionality.
- If this is a Surface device, do a hardware reset for the USB-C port:
- Unplug the USB-C device.
- Select Start > Power > Shut down.
- After 10 seconds, press and hold the Power button for about 20 seconds until the Windows logo appears, disappears, then appears again.
- Plug the USB-C device back in.
- Then open the Surface app > Help & support and install any available driver or firmware updates.
If HDMI works but USB-C video does not, the most common causes in this scenario are:
- the USB-C port does not support video output,
- the dock or cable does not support the required Alternate Mode,
- the dock is connected through an unsupported path,
- or the laptop’s graphics hardware cannot support two external extended displays.