Symptoms
- Monitor shows 'No Signal' when connected via USB-C
- USB-C connection charges the laptop but shows no video
- Video works fine when using HDMI or DisplayPort instead
- Cable or dock worked with a different laptop
Likely causes
- CommonUSB-C port doesn't support video output (DisplayPort Alt Mode)Not all USB-C ports carry video signal; some are data/charging only.
- CommonUSB-C cable doesn't support video (charge-only cable)Many cheap or charging-focused USB-C cables lack the wiring needed for video.
- PossibleDock or hub not properly passing through videoSome docks require specific driver software or don't support the monitor's resolution.
- PossibleLaptop's graphics settings not routing video to the USB-C portSome laptops need a setting enabled to allow external video output over USB-C.
What to do
- Check your laptop's specifications to confirm the USB-C port explicitly supports video output (often labeled 'DisplayPort over USB-C' or has a small DisplayPort or monitor icon next to it).
- Try a different USB-C cable, ideally one explicitly rated for video/DisplayPort, not just charging.
- If using a dock or hub, install any required driver software from the dock manufacturer.
- Test the same monitor with HDMI or DisplayPort directly to confirm the monitor itself works.
- On Windows, check Display Settings and click 'Detect' after connecting via USB-C.
- Try a different USB-C port on the laptop if it has more than one, since not all ports are wired identically.
Tools and parts
- None
USB-C to DisplayPort/HDMI cableSearch: “USB-C DisplayPort alt mode cable”
When to call a pro
If your laptop's port genuinely doesn't support DisplayPort Alt Mode, no cable will fix it; a USB-C dock with a dedicated display adapter chip, or using HDMI/DisplayPort instead, is the practical solution.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.