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Macbook Pro- Unable to detect second HDMI external display through USB C adaptor

I am running into issues with my macbook pro (M1, 2020, macOS Monterey 12.3.1) and trying to detect my second monitor. For reference, I have two external monitors I am trying to use, using two USB C adaptors and for some reason my macbook pro will only connect to one. The other one says 'no signal' then goes blank.

It is not a faulty USB C adapter because I have the macbook charger connected to the one where the HDMI for the monitor is not displaying, and it is charing my macbook so the adapter itself is working, it just cannot detect the HDMI.

It's almost as if this macbook pro cannot detect two HDMI's at the same time because when I unplug the USB C adapter that is working, the macbook pro after a couple of seconds, will detect the one that initially wasn't working.

My 2019 macbook air (also on macOS Monterey 12.3.1) can detect both of the adapters fine and will connect and display both monitors so not entirely sure why my macbook pro cannot.


Posted on Apr 8, 2022 7:43 PM

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Posted on Apr 8, 2022 7:50 PM

The M1 Macs only support one external display.

MacBook Pro (13-inch, M1, 2020) - Technical Specifications

"Video Support 

Simultaneously supports full native resolution on the built-in display at millions of colors and: 

  • One external display with up to 6K resolution at 60Hz"


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Macbook Pro- Unable to detect second HDMI external display through USB C adaptor

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