Target Display Mode not working 2020 MacBook Pro (Catalina)

I have exactly the same problem. I want to use my IMac mid 2001 27 inch (MacOS High Sierra) as a target display of my new macbook pro 13' 2020 (MacOS Catalina).

I always used the Imac 2011 as the target display of my macbook 2014 and worked fine through a thunderbolt cable!

Now, with the macbook pro 2020 I bought the Thunderbolt 3 to thunderbolt 2 adapter hoping to use the Imac 2011 as the target display of the new macbook 2020. Nevertheless, after receiving the adapter I connected the two macs (the macbook 2020 with the Imac 2011) but nothing, when I press Command+F2 on my Imac 2011 nothing happen.

I called the Apple support and after 2 hours of trials they CONFIRMED that actually from macbooks 2020 onwards this functionality (IMac 2011 as target mode with the newest macbooks) is not supported anymore. So, the adapter is totally useless, this is why I am returning back the adapter to Apple.

I am quite frustrated and angry with Apple.

If someone finds a solution please let me know. Thanks!

Maybe I can add something here: the iMac 27 from 2009 has a mini Displayport and no thunderbolt on the back side and this one worked with my MBP 2020 with a non Apple USB-C to mini Displayport cable. Seems like with this model you can have any input device (also PCsor so) as it hasn't a thunderbolt connector yet. Maybe this helps somebody.

I have exactly the same problem.

My MBP from 2019 is working together with my iMac 27 (mid-2011) in Target Display Mode but not the newest MBP from 2020, I bought recently.

Pretty disappointing, Apple!

Cannot this be considered as a flagrant example of programmed obsolescence, just made intentionally for people to buy more display screens, to the detriment of the planet?

Apple has always been very sensitive to this...

Cannot this be considered as a flagrant example of programmed obsolescence, just made intentionally for people to buy more display screens, to the detriment of the planet?

No. That only computes if consumer-grade displays were a core Apple business segment. As Apple now have only one display that starts at US$5000 😳, I would say they are not in the consumer display business.

And remember this process of depreaction started SIX years ago.

If a third-party prints incorrect information on some blog or FaceBook posts, who is really responsible? Can any company police the entire Web? No.

When I see stuff like that, I don't blindly head out to buy; I check Apple's specs and support documents first.

Dear Grant, I'm sorry it's not the iMac where the problem is. The iMac perfectly supports this function, and will do till its end of life. It's the MBP that does not support this function anymore. I have bought one in Feb 2020. It did. I was burgled and lost it. I bought exactly the same one, got it one month ago. And it does not work anymore.

It's an hardware "upgrade". That basically will make me buy another "modern" display that will never match the resolution I had on my iMac unless I pay a fortune.

Support for that feature was removed from MacBook Pro and others for the 2020 model year.

Maybe you old Mac was a 2019 model, or maybe a production error. But now, that feature is not supported in 2020 Macs and beyond, and it is not likely to be re-instated.

Dear Grant,

If the feature is officially removed, why is it not Written anywhere since I bought a new one for almost €4k?

Tell me please a good reason for this? Beyond making millions of old imacs going to the bin as they are now becoming useless as just displays.

(but yes my Mac delivered feb 20 should have been delivered sooner, but was 8 weeks delayed due to Covid In China. The model was probably indeed a 2019 model! You may be right!).

But this still does not provide me a reply to the previous point! And even though you are vehemently defending the issue, I really cant find any good motivation for it beyond a pure mercantile one.

One possible reason is that they wanted the space in the ROM for additional features, especially considering that the Apple-Silicon M1 Macs were being developed.

Apple does not add new features for products no longer for sale, and the last iMac that supported that feature was a mid 2014 iMac, discontinued October 2015.

The right adapter of course! The display has its own thunderbolt 2 cable (that looks like the mini display port), that goes into an apple thunderbolt 2 female to the thunderbolt 3 (usb-C) one in the MBP.

Your new 2020 MacBook Pro does not have a thunderBolt-2 port. are you using an adapter? which one?

What identifier is shown on the 27-in display you bought? I ask because there are TWO identical-looking Aluminum-frame 27in displays -- one is Mini DisplayPort and the other Is Thunderbolt-2, and if you got the Mini DisplayPort version, it would behave EXACTLY as you describe.

I just bought a MacBook Air 2020 with the newer M1 models and a cable to connect with my 2011 iMac. With my previous MacBook Pro I could use it as a screen but with this one it does not work. They did not told me so when I purchased the Thunderbolt 3 - Thunderbolt 2 adapter, which is quite expensive.

Very dissappointed.

For a company that is proud to say they care about the environment they sure rather my late 2013 iMac end up in a land fill polluting ground water and the environment then be used for another 5 - 10 years as a monitor. I’d be glad to chunk the the old iMac into the ocean for them and go buy a competition monitor that will prob last 1-2 years and throw that right into the ocean too! Way to Apple! Pushing people the brink of ruining the environment.

maybe i can help, on youtube there was a guy, using a dock with its own thunderbolt controller and a bunch of dongles that do video over usb, to connect up to 5 or 6 displays to the new M1 macs, check it out: ***

perhaps one of those solutions/docks/cables/dongles can work for you?

also...

while my own mba M1 is still waiting to be shipped, i would like to know from others here, if it's true or not that any mac with a mini display port connector, such as 2009/2010 imacs can be successfully connected in TDM to an M1 mac using said solutions of the above video.

From reading all pages here, I suspect that will work, as the problem with newer combo's seems to be the thunderbolt limiting interoperability, while a mac with display port connecter, would most likely present as a vanilla display port monitor to any other device, when switched to TDM after it's booted and logged in.

I do hope so, because i got a 2010 imac which i want to use as a monitor on the m1 mac, nekt to a dvi equipped dell 24'' monitor from yesteryears.

[Link Edited by Moderator]

DisplayLink technology creates a "fake" display buffer in RAM, sends the data out over a slower interface to a stunt box with DisplayLink custom chips that put that data back onto a "legacy" interface. It is not a true "accelerated" display, and it suffers from lagging.

It may be acceptable for a second display showing slow-to-change data such as computer program listings, stock quotes, or spreadsheets, but NOT for full motion Video, not for Video editing, and absolutely not for gaming. Mouse-tracking on that display can lag, and can make you feel queasy.

In a pinch, it may even play Internet videos without (as one user put it) "too many dropped frames".

This is in stark contrast to the Apple standard for its built-in hardware-accelerated displays ,which are suitable for production/display of cinema-quality video with NO dropped frames, and NO dropouts or partial-blank scan lines due to memory under-runs or other issues.

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It is really nice to know that you can use a DisplayLink display if you MUST have an additional display for some of the types of data I mentioned. But that is NOT the same as the computer supporting a second, built-in, Hardware-accelerated display.

These displays depend on DisplayLink software, and are at the whim of Apple when they make MacOS changes. There have been cases where MacOS changes completely Borked DisplayLink software, and it took some time for them to recover.

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I think the Big Surprise for a lot of Hub/Dock buyers is that they thought they were getting a "real" display, but actually got a DisplayLink "fake" Display. If you got what you expected in every case, I would not use such pejorative terms to describe DisplayLink.