Use iMac screen for 2020 M1 Mac mini?

I had TDM set up from my 2015 MBP (which had Thunderbolt 2 port) to 2011iMac via T2 cable for a couple of years. So, today I got my M1 Mac Mini, and just added an Apple T3 to T2 adapter and the same 2011 iMac - pressed Cmd-F2 just like I had for years and Nothing Happened. I will keep googling, but it doesn’t look promising. If no go, I’ll look at Screen Sharing or a new monitor. But not yet.

The whole point of the mini was that you *already* had the keyboard and monitor from another computer. Besides, basic monitors are so cheap, Apple does not want to play in that space.

But, feel free to send Apple feedback saying you want something side-car like on the mini:

https://www.apple.com/feedback/

No 2020 Macs support Target Display Mode, either as the source or the target computer.

Sysreqs here, but note even the support article is archived:

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

Apple started the deprecation of TDM six years ago when the last iMac that could serve as an external monitor was the Mid 2014 model, and finished it off for good early in 2020. It's dead.

Displays are cheap now. I have a M1 mini on order, and the first order of business is to connect it via HDMI to an existing 40 inch 4k Upscaling TV to assess the resolution and color. That 40 inch TV cost $166 via Walmart and is presently serving as the primary desktop for Windows 10 2H20. This might become my replacement Desktop, as I move the current iMac to another area of my desk.

At any rate, you will need some external monitor to setup the M1 mini, and then from there, you can configure the built-in screen sharing and serve the mini desktop virtually over the network to the iMac using the included Apple Screen Sharing application.

SomeoneHasToSayIt wrote:

Bottom line on at least my 2013 iMac, it can be used for a 2nd display for a 2019 MacBook Pro, but not from a Mac mini. Why?

"You can connect any of these older iMac models to another Mac from 2019 or earlier for use as an external display"

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

The now-archived tech article on TDM is not clearly presented. This is the information on hardware (less cabling info) rearranged for us normal people, and with newer info that won't get added to an archived article:

VIDEO SOURCE COMPUTER (the one sending the video signal to an external monitor):

• • A 2019 or older Intel Mac running macOS 10.15 Catalina or older.
  • M1 Macs and Big Sur mac OS11 are not supported.

TARGET COMPUTER (the one to be an external monitor):

• • An iMac 27-inch (Late 2009 and Mid 2010), or any iMac from Mid 2011 to Mid 2014.
  • The target computer can run no higher macOS than OS 10.13.X High Sierra

Just so that it picks up the thunderbolt connection first, I turned off wifi on both before trying to connect. Then when the connection and screens are shared turn on wifi and it connects to the internet via wifi and thunderbolt for the screen sharing. Seems to remember it after the first time too. I have only had to do it once or twice. Both have good internet connection whilst having a good frame rate on the screen sharing.

Whilst not having the same screen refresh rate, it really is not too far behind at 30-50 if using adaptive 30+ for full quality rather than 60 (its not perfect). Lower the display resolutions for higher frame rate.

You do get the added bonus of having the Mac Mini in a window or full screen, very fast file sharing, shared keyboard, mouse and track pad and this should work with any mac not just those that used to have TDM

I did make a video but it looks more choppy than it really is. I think it is due to the screen recording being at 25fps and doesn't show it as smooth as it really is and hence my estimate of 30+.

Here is a screen shot!

Soundboutique wrote:

I've got a 2020 iMac and thinking about getting an M1 Mac mini... would be nice if I could use my iMac

as a monitor to switch back and forth between the two. Is there any way to do this?

No. Target Display Mode is not supported on iMacs since 2015. It has nothing to do with M1 Macs.

On the newest Mac mini :

I can already see a major setback to the cheaper cost of the Mac mini. What is an entry level person just newly getting a Mac mini supposed to do for monitor? The Pro XDR is 5 grand.

There's no need for a Pro XDR. Any compatible monitor will work as noted.

That 2012 iMac needs to be running macOS High Sierra or earlier for target display mode, and the appropriate cabling between the two. Then there is also Apple's VNC screen sharing between the devices.

I have had a similar setup, a MacBook pro 2016 and 2011 iMac. I just received the M1 Mac Mini, and like you can confirm that it will definitely not work with TDM.

Alternatively I am using the built in VNC Screen Sharing with the same thunderbolt cables and adapter as a local network between the M1 Mini and iMac (very fast) and a cheap 4k headless HDMI adapter from amazon with really great results. Don't get me wrong it is not quite the same but it is very usable as a stop gap until my new monitor arrives. I'll be using my iMac as a second display after that!

Charlievarley66 wrote:

....

Alternatively I am using the built in VNC Screen Sharing with the same thunderbolt cables and adapter as a local network between the M1 Mini and iMac (very fast) ...

How did you do that and maintain an internet connection on either the

Mini or the iMac.

Well Interesting enough, I have a late 2013 iMac, and I got a Mac mini today. After watching several videos and consulting with them at the apple store I brought home a Thunderbolt 3 to thunderbolt 2 adapter and a .5 m Thunderbolt cable. So I plugged in the Mac mini set it up with monitor over HDMI and then tried to connect the new adaptor and cable to one of the two Thunderbolt 4 ports (USB-C type ports on the back of the Mac mini) nothing happened. I hit the Command + F2 key an still nothing. Tried Fn Command F2 and still nothing.

So then I pulled out my 2019 MacBook Pro and too the usb-c end of the adaptor out of the Mac mini and plugged into MacBook Pro. Then hit command + F2 and bingo it worked. Tried several times and it worked every time, yet when connected to the Mac mini doesn't work. Yet those ports not he Mac mini seem fin as I can run thunderbolt 3 hub out of them and use the HDMI from the hub to power a 4k tv as a monitor, so the ports on the Mac mini seem to be fine.

Bottom line on at least my 2013 iMac, it can be used for a 2nd display for a 2019 MacBook Pro, but not from a Mac mini. Why?

Unfortunately target display mode is no longer a thing. All new Macs will no longer be able to use it.

With a cheap headless hdmi adapter I am now using my 2011 iMac via screen sharing as a second screen at 1440p (see my other posts). My main screen now is a new 4k LG monitor.

A suggestion.

I have a Late 2013 iMac with 32gb, i7 blah, blah blah.

I hope they find a work around to allow iMac users to make the most out of their older machines still in good condition and M1 TDM is welcome back anytime.

No, I have not gotten it work. SO it looks like I either have to forget using this nice screen, and sell the iMac invest in another 4k type screen or return the whole iMac. Unfortunately I dont have room on my desk fro yet another monitor. I already have a 43" Sharp 4k tv I use for my work monitor and next to it Have my iMac and they both barely got, in fact I have to my iMac angled towards me. .