EXTERNAL 4K DISPLAY

Hi Kevin Bouah,

Thanks for reaching out to Apple Support Communities.

It sounds like you're having an issue connecting your external display to your Mac.

We're happy to assist.

We recommend checking out the steps in the section titled "Connect the display to power and your Mac" from the article here: Connect a display to your Mac

1) Use your display's power cable to connect the display to power.

2) Use your display's video cable to connect the display to your Mac, such as to a Thunderbolt  or HDMI port. Different ports might look similar, so it's important to identify the port correctly.

3) If the video cable requires a port that your Mac doesn't have, you might be able to use an adapter with the video cable. Or replace the video cable with one that doesn't require an adapter.

4) When your display has power and is connected properly, your Mac detects the display automatically. You should then see your Mac desktop on the display, and you can configure display settings.

If your display isn't detected or can't use its highest resolutions or refresh rates, learn what to do if your display has a dark screen (no video) or low resolution.

Configure display settings

From the Apple menu  in the corner of the screen, choose System Settings (or System Preferences), then click Displays. In display settings you can change display resolution, choose a refresh rate, arrange your displays, and more.

If the display is not made by Apple, certain settings might be available only by using the display's built-in controls and menu system. Check your display's documentation for details.

We're recommending the steps above because they directly address the issue you initially posted about: you're having difficulty with the external display connected to your Mac.

Should the issue continue, follow up with the steps in this article: If your external display is dark or low resolution

Please let us know the outcome after giving the above steps a try.  

Cheers!

Use a different USB-C to 4K HDMI adapter that supports HDMI 2.0a or 2.1 specs. Belkin makes one of these that is available in the online Apple Store, and you should also have modern (HDMI 2.0a, HDMI 2.1) cable for the final leg to your HDMI 2.0a display. On a 2020 device, Apple does not provide more than 60 hz 4K (3840 x 2160) resolution to an external display.

I have used both from my 2020 M1 mini, or just the cable to my 32-inch LG 4K UHD HDR display and it works like a charm at the expected 4K resolution.

You are welcome.