MacBook 2024 Air M3 not allowing two external monitors.

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Level 1

4 points

MacBook 2024 Air M3 not allowing two external monitors.

My 2024 MacBook Air M3 is not allowing me to connect two external monitors. I have two Apple USB-C to Digital AV adapters. Both have an LG Ultrawide monitor connected via HDMI. When I close the lid, only one screen is recognized. I can unplug one and plug the next in with the same result. Each screen will work in both ports, but not at the same time. What am I missing? The Apple Store tech today told me this should work fine. I purchased the second port today and it's not allowing both to connect still.

The only thing I have not thought of is that my Magic Keyboard and Magic Mouse are connected via universal control on my other computer. Would pairing them directly to the laptop fix this? Closing the lid does seem to activate clamshell mode regardless. I am connected via power, and have an Apple USB-C Digital AV port connected to each Thunderbolt port. Both monitors have their own power and I am on the latest MacOS.

Thank you.

Posted on Dec 6, 2025 3:57 PM

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Answer 1

Dec 6, 2025 4:27 PM in response to bleznyk1

Use dual monitors with your MacBook Air and MacBook Pro with M3 chip - Apple Support

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Answer 2

Dec 6, 2025 4:30 PM in response to bleznyk1

A remote possibility is that the vendor programmed the monitors incorrectly, to have the same electronic serial number / ID.

But it’s probably something else, like not meeting the requirement for an external keyboard and an external pointing device.

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Answer 3

bleznyk1 Author

Level 1

4 points

Dec 6, 2025 4:34 PM in response to Servant of Cats

By "external", does this mean Bluetooth? I have Magic Mouse and keyboard, but through UC on my mini. Unpairing that will leave the mini useless. I just tried Logitech bluetooth mouse and keyboard with the same result. I have been through the article and tried all the steps.

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Answer 4

bleznyk1 Author

Level 1

4 points

Dec 6, 2025 4:37 PM in response to Servant of Cats

My keyboard and mouse are connected with the lid closed on the working external display.

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Answer 5

bleznyk1 Author

Level 1

4 points

Dec 7, 2025 7:36 AM in response to Servant of Cats

I have paired both magic mouse and keyboard to the M3 air with the same result. I also tried a Logitech mouse and keyboard with the same result.

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Answer 6

Dec 6, 2025 4:44 PM in response to bleznyk1

Re: “The only thing I have not thought of is that my Magic Keyboard and Magic Mouse are connected via universal control on my other computer.”

I think by “external”, they mean that the keyboard and pointing device are plugged in, or possibly paired with, the M3 MacBook Air. Not connected to another computer and shared from it via Universal Control.

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