How to turn a Mac into an external monitor

The consensus is that iMacs are the jewel in the crown of desktop computers, but the trend is what it is: the public is moving more towards portable devices to get around with their computing. And for this case, it is best to connect it to a monitor at home.

But what if you don’t have a monitor at home but a desktop Mac instead? Well, there are options too Use this Mac as an external monitor. Let’s see how we have to achieve it.

What Mac models can become an external monitor

Not every Mac can be used as an external monitor for another Mac, and there are two different ways to do this. If you want to do it with AirPlay, you must have one of the following Macs as the “Receiver”:

  • MacBook Pro or MacBook Air from 2018, including MacBook Air M2
  • iMac from 2019, including Mac mini M1
  • 2017 iMacPro
  • 2019 MacPro
  • Mac mini M1 and Mac mini M2 or M2 Pro (of course with a connected monitor)

On the other hand, if you want to connect your Mac via cable to the other Mac that you want to use as a monitor, then the requirements are even higher since you can only use some older iMacs:

  • 24″ and 27″ iMac 2009 and 2010 with macOS High Sierra installed
  • 2011, 2012, 2013, and Mid-2014 iMac with macOS High Sierra installed

In this case, you will also need a Thunderbolt cable of the version that the Macs you are using have (Thunderbolt 1 or Thunderbolt 2), or a miniDisplayPort cable if they are 2009 or 2010 Macs. In any case, the Mac you use to extend your desktop must be one from 2019 and you must have macOS Catalina or a later version installed.

How to turn a modern Mac into an external monitor

In this case, we can use AirPlay to “broadcast” a second monitor to another Mac. All we have to do is open both computers in the same Wi-Fi network (if we connected it by cable it works too). and on the Mac we want to use, look for the ‘Mirror Screen’ option in the Control Center:

Mac Screen Mirroring Airplay

Mac screen mirroring

You will see that after a few seconds the other Mac will mirror the screen of the first one and you will have an icon in the menu bar indicating this. If you press it, you will see that you have the option to clone Mac’s main screen or extend the desktop:

mac screen mirroring extended desktop

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How to convert an old iMac with an external monitor

If you want to connect one of the older iMacs mentioned above, simply turn on both computers and log in to their respective systems. Then connect them via their miniDisplayPort or Thunderbolt 1 or 2 connections and On the old iMac, press CMD + F2 keys. You’ll see the iMac suddenly display the other computer’s desktop.

To undo this and restore the original desktop from the old iMac, just press CMD + F2 again.

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