How to use iMac as a monitor for my Mac mini?

I have connected the M1 Mcmini to the Thunderbolt port on the iMac with a USB 4/Thunderbolt cable. How do I see the Mini on the iMac?




[Re-Titled by Moderator]

Original Title: M1 Macmini & 2017 iMac

iMac 21.5″ 4K, macOS 13.7

Posted on Aug 13, 2025 12:02 PM

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Question marked as Top-ranking reply

Posted on Aug 13, 2025 12:24 PM

+1


The 2017 iMac is an all-in-one computer.

It does not have external video input or support being use as a display for another computer.


FWIW you can use most any after-market External Display or HDMI TV with a Mac mini.

see > Connect a display to Mac mini - Apple Support

12 replies

Aug 13, 2025 5:51 PM in response to seanfromsligo

They can talk to each other over that Thunderbolt connection.


I believe that you could set them up in Thunderbolt Bridge mode – so that the Thunderbolt connection acts in a similar way to an Ethernet network link. Once that network connection was configured, you could configure File Sharing or Screen Sharing. Note that Screen Sharing is NOT a way of allowing you use that iMac as a substitute for a real monitor.


You could also boot up one of the machines in Target Disk Mode or the equivalent. Then that machine would act as an external disk for the other. I don't see this as something one would want to do long-term – but there might be occasions where it would be handy.


Finally, if you were setting up the newer Mac from scratch, I believe that Migration Assistant could pull stuff from the old Mac over a Thunderbolt link.


But as for the iMac acting as a Target Display – nope. That ship sailed in Late 2014.

Aug 14, 2025 11:14 AM in response to seanfromsligo

..So Apple makes 2 machines 3 years apart......and they can't talk to each other.......naver expected that from Apple


How did you research this? Who told you that Target Display Mode would work? The amount of gross misinformation about TDM on the web that started with the work-from-home needs of COVID would sink a supertanker.


Apple covers it. The very restrictive hardware and system software requirements under which the now-defunct TDM once operated are clearly laid out in this Apple article:


Use your iMac as a display with target display mode - Apple Support


I see nothing ambiguous there.


Apple began the deprecation of TDM over ten years ago, and threw the final shovel of dirt in its face over five years ago.






How to use iMac as a monitor for my Mac mini?

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