macOS Monterey lets you use a second Mac as an external display

macOS Monterey lets you use a second Mac as an external display


macOS Monterey turns a second Mac into an external display
And you can USB for reduced latency.
Photo: Apple

macOS Monterey gives newer Apple computers the ability to send content to a second Mac over AirPlay. You can also use the feature for screen mirroring, turning a spare machine into an external display.

What’s more, unlike on your TV, AirPlay in Monterey lets you connect two macOS devices with a USB cable, greatly reducing latency and removing the requirement for a wireless network.

AirPlay has long been making it incredibly easy to wirelessly stream audio and video from your iPhone, iPad or Mac to an Apple TV. In recent years, the technology has also expanded its reach to third-party TV sets.

Enable screen mirroring on your Mac and you can quickly turn a compatible AirPlay screen into a second display. And in macOS Monterey, you can now do the same with a spare Mac.

macOS Monterey turns a spare Mac into a second screen

“Use AirPlay to send content to your Mac from an iPhone, iPad, or even another Mac,” reads the macOS Monterey preview page. “View videos, edit Keynote presentations, and hear music on your Mac as it’s being played from your other device.”

“When you send content from your iPhone or iPad to your Mac, you can choose to mirror your iPhone or iPad or extend its display by using a Mac as a secondary display for apps that support it, such as Keynote and Photos.”

What Apple’s description doesn’t mention is that it’s also possible to mirror or extend one Mac’s display onto another, as confirmed by MacRumors. And if you’re working without a Wi-Fi connection, you can connect both devices over USB instead.

Using USB may be favored even when a Wi-Fi network is available for a smoother, more responsive connection. However, because AirPlay automatically compresses content before streaming it to a second device, it’s unlikely latency can be eliminated entirely.

You need a recent Mac

So, AirPlay isn’t quite a revival of Target Display Mode, a feature that allowed 2009 to 2014 iMac models to be used as a second display for another Mac. But it could well be incredibly useful to some. You will need two recent Macs to take advantage of it, however.

AirPlay to Mac will be available on the following machines:

  • 2018 or later MacBook Pro
  • 2018 or later MacBook Air
  • 2019 or later iMac
  • 2019 or later iMac Pro
  • 2019 or later Mac Pro
  • 2020 or later Mac mini

macOS Monterey is scheduled to make its debut this fall and will be a free upgrade for all compatible devices. Developers can get their hands on the first beta now, while a public beta should be available later.