Unable to connect secondary monitor (2019 iMac) to my new MacBook Air M1

Having trouble using my 2019 iMac 21.5" as an external monitor for my MacBook Air M1. Devices are connected via Thunderbolt 3 cable. Macbook air won't detect secondary monitor although charging works. Thanks in advance for any help.

Posted on Apr 28, 2021 04:56 PM

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Posted on Apr 28, 2021 05:21 PM

Unfortunately, your setup will not work to use your 2019 iMac 21.5" as an external monitor. What you are attempting to do is called using the Target Display Mode. Target Display Mode isn’t supported on iMac models with Retina display. Only iMac (27-inch, Late 2009), iMac (27-inch, Mid 2010), and iMac (Mid 2011 to Mid 2014) support Target Display Mode.


Axel F.

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Apr 28, 2021 05:21 PM in response to maxben73

Unfortunately, your setup will not work to use your 2019 iMac 21.5" as an external monitor. What you are attempting to do is called using the Target Display Mode. Target Display Mode isn’t supported on iMac models with Retina display. Only iMac (27-inch, Late 2009), iMac (27-inch, Mid 2010), and iMac (Mid 2011 to Mid 2014) support Target Display Mode.


Axel F.

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Unable to connect secondary monitor (2019 iMac) to my new MacBook Air M1

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