Macbook Air M1 no longer recognizes Acer external monitor

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Level 1

5 points

Macbook Air M1 no longer recognizes Acer external monitor

MB Air M1 2020 OS 15.5 no longer recognizing external Acer K273E monitor via HDMI. After connecting the MBAir to my Samsung smart TV to play a movie my Acer monitor no longer appears as an external monitor in Display settings. When I plug the adapter into the MBAir the Acer monitor turns on and LCD appears to be on, but no image. Here is what I have done to troubleshoot this issue:

-Restarted MBAir

-Switched to a different HDMI adapter

-Reset Acer monitor to factory

-Made sure Acer monitor is set to HDMI input

-Replaced HDMI cable

-Checked display settings, Option key detect displays, and changed resolutions

-Confirmed MBAir has power cord plugged in and working

-Connected MBAir with same HDMI adapter to old Apple Studio Display and display shows MBAir screen as extended and mirrored. Display settings shows both monitor

-Connected Acer monitor to 2010 Mac Mini HDMI port using same HDMI adapter and Acer monitor shows MacMini display.

I do recall that when I connected the MBAir to the Samsung TV I was asked to choose which App to display. Which I did and I was able to watch the movie on the Samsung.

MacBook Air 13″, macOS 15.5

Posted on Aug 23, 2025 04:57 PM

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Answer 1

robwinston Author

Level 1

5 points

Aug 23, 2025 06:13 PM in response to robwinston

Update: Updated to Mac OS 15.6.1. When I wake MBAir display the Acer monitor power light comes on and LCD screen is on but no image. Dragging windows to left or right on MBAir doe not move them to Acer monitor. The Acer monitor still does not show in Display control panel.

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Answer 2

Aug 23, 2025 11:01 PM in response to robwinston

If the Acer display showed up in Displays Settings, but you had things set to mirror mode, I’d wonder if mirror mode might be trying to use some resolution the Acer monitor did not like.

But you say it is not even being detected as a display?

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Answer 3

robwinston Author

Level 1

5 points

Aug 25, 2025 12:37 PM in response to Servant of Cats

I believe this might be an hardware issue with the MBAir C Port or possibly with my third party HDMI adapter. I will order a genuine Apple HDMI-C adapter to confirm. It is still odd that both my 3rd party adapters work correctly with other external monitors and with my MacMini and HP Chromebook. and has worked with my MBAir for the past 5 years.

There was another similar discussion that the external monitor only worked when the MBAir was closed. I closed my MBAir and unplugged and plugged in the HDMI adapter to the C-port and the Acer monitor now shows as mu primary monitor. However, in the Apple display settings only the Acer monitor appears, and allows me to change resolutions and refresh rates for the Acer monitor. If I open the MBAir the Acer monitor goes blank and the MBAir display becomes the primary monitor. I also noticed that when I have to wake up the MBAir, and Acer monitor is connected and MBAir cover closed, the screen initially shows as a lower resolution, then switches to the Acer default resolution 1920x1080.

So for now I am able to use the external monitor, but not the MBAir and External simultaneously, which is not a problem, but I will still try the genuine Apple adapter, when received, and update this discussion.

Thank you for the input and responses :)

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Answer 4

robwinston Author

Level 1

5 points

Aug 25, 2025 07:18 PM in response to paundrapujo

See my reply of 8/25 stamped 9:37 AM. Try closing your Macbook cover and unplugging and plugging the adapter in again to the USB-C port. This made my external monitor work, but if I open the MB cover, the external monitor goes dark and the built in LCD becomes the primary monitor. This is at least a partial fix. I think this might be hardware related with the USB-C ports or possibly the adapter. Although, I have two adapters made by the same company that were working previously and now both exhibit the issue.

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Answer 5

Aug 23, 2025 05:44 PM in response to robwinston

The M1 MacBook Air only supports one external display. Were you trying to connect it to your Samsung TV and your Acer monitor at the same time?

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Answer 6

robwinston Author

Level 1

5 points

Aug 23, 2025 06:09 PM in response to Servant of Cats

No- Just the Acer as it had been connected to and working the day before yesterday.

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Answer 7

Aug 25, 2025 04:39 PM in response to robwinston

Hi, have you solved the problem? I am experiencing the same problem as you, but with a different brand. I have also tried all the troubleshooting steps you wrote and still haven't found a solution.

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