Connect a second monitor or TV to your Mac

Why it happens

Your Mac sends video through its Thunderbolt or USB-C ports, and some models have an HDMI port too. Most monitors and TVs need either a matching cable or a small adapter, such as USB-C to HDMI. Once it's connected, your Mac stretches the desktop across both screens by default.

How to fix it

1. Find a video port on your Mac. Thunderbolt and USB-C ports carry video on Mac laptops and desktops, and some models also have an HDMI port. Use a USB-C to HDMI or USB-C to DisplayPort cable or adapter if the monitor needs one.

2. Plug in the cable, turn the monitor or TV on, and choose the matching input on it, such as HDMI 1. The screen should light up with your wallpaper within a few seconds.

3. Open the Apple menu, choose System Settings and click Displays. Click Arrange…, then drag the screen pictures so they match where the monitors sit on your desk. Drag the white bar to the screen you want as your main one.

   Displays›Arrange…

4. Want the same picture on both, for a TV or projector? Click the monitor in Displays and set Use as to Mirror. Choose Extended display to go back to two separate screens.

   Displays›Use as

Still not fixed?

1. If the monitor stays black, check the cable at both ends and the input on the monitor. Then in Displays, hold the Option key and click Detect Displays, which appears in place of Night Shift….

   Displays›Detect Displays

2. Try another cable or adapter, and plug straight into the Mac rather than through a hub. Not every USB-C cable carries video, especially thin charging cables.

3. Check how many screens your Mac supports. A MacBook Air with M1 or M2, and a MacBook Pro with a base M1, M2 or M3 chip, support one external display. A MacBook Air with M3 can run two with its lid closed. Apple's tech specs page for your model gives the exact number.

4. If the picture fits badly on a TV, with edges cut off, look for Underscan in Displays when the TV is selected, or set the TV's own picture size to Just Scan or Screen Fit.

5. Restart your Mac with the monitor plugged in. If it works with other computers but never with your Mac on any cable, contact Apple Support, as the port may need a repair.