There’s no switch in Windows 10 to turn on DP Alt Mode. DisplayPort Alternate Mode is a hardware feature: a USB-C port either supports video output or it doesn’t. To use it, plug your monitor into a USB-C port marked with a DisplayPort or Thunderbolt icon, using a USB-C to DisplayPort/HDMI cable or adapter that supports video. If nothing appears, update the graphics and USB-C drivers and your PC’s firmware, then check the port’s specs with the maker.
Windows 10 reached end of support on October 14, 2025. Consumer Extended Security Updates (ESU) now run until October 12, 2027.
Quick Answer
Use a USB-C port with a DisplayPort or Thunderbolt logo and a video-capable cable. Then press Windows + P to choose how to use the screen.
Step 1: Check the Port
- Look for a small DisplayPort (D-shaped) or lightning-bolt (Thunderbolt/USB4) icon next to the USB-C port.
- No icon? Check your laptop’s spec sheet or support page for “DisplayPort Alt Mode” or “video out.”
- Some USB-C ports are data and charging only and can’t carry video at all.
Step 2: Use the Right Cable or Adapter
| Connection | What you need |
|---|---|
| Monitor with USB-C input | A full-featured USB-C cable (not a charge-only cable) |
| DisplayPort monitor | USB-C to DisplayPort cable |
| HDMI monitor or TV | USB-C to HDMI cable or adapter |
| Several screens | A USB-C or Thunderbolt dock rated for your laptop |
Step 3: Update Drivers and Firmware
- Run Windows Update, including optional driver updates.
- Install the latest graphics driver from your PC or GPU maker.
- Update the BIOS/UEFI and any Thunderbolt or USB-C controller firmware from the PC maker’s support site.
Step 4: Set Up the Display
Press Windows + P and choose Duplicate or Extend, or open Settings > System > Display. See extending your display for arrangement tips.
Troubleshooting
- “USB device may not work properly” or “Display connection might be limited”: Windows is warning that the port, cable or dock doesn’t support the full video mode. Try another port or cable.
- Works on one port only: Only that port supports video.
- Flickering: Use a shorter, certified cable, and set a lower refresh rate or resolution.
Frequently Asked Questions
Can software add DP Alt Mode to a port?
No. It depends on the port’s wiring and controller.
Can I use a USB display adapter instead?
Yes. DisplayLink-style adapters work over ordinary USB with their own driver, but may perform less well for video and games.
Summary
- DP Alt Mode is hardware, not a setting.
- Use a USB-C port with a DP or Thunderbolt icon.
- Use a video-capable cable or adapter.
- Update drivers and firmware, then press Windows + P.
Kermit Matthews runs Live2Tech from just outside Philadelphia. He is an IT specialist with over 20 years of experience, from a university help desk to small-business IT, IT management and his own consulting practice, and has written tech guides full time since 2020. Steps are checked against the current software on a real device or the maker’s official documentation. More about Kermit.