Using old iMac as a Secondary Monitor Apparently No Longer Works

Apparently, although the hardware obviously can support this, in Mac OS Monterey (and maybe earlier), Apple has taken away this feature.

Target Display Mode was not supported on iMac models with Retina display.

Only iMac (27-inch, Late 2009), iMac (27-inch, Mid 2010), and iMac (Mid 2011 to Mid 2014) supported Target Display Mode.

On an Apple Keyboard: Command-F2 would put your old iMac into Target Display Mode.
On an Anker Keyboard: Command-F3 would do the same.
old iMac into display mode!

But of course, if you've upgraded your OS, none of this will work.

Using an old iMac as a Secondary Monitor No Longer Works

[SteveBoyer]

Now we know why… keeping this feature would cut into their Studio Display sales, which is virtually the exact same display.

[EddieSprouse]

It is a shame Apple has so much control over what you can do with their hardware. Seems petty to me. But they do make good stuff.

[thetmjhealer]

I've spent days reading, listening to videos, and spending money on buying cords and adaptors, ALL FOR NOTHING! What a selfish move on Apple's part. What they've done is contrary to their belief system, which is to make things easier for the customer. Their whole premise of the company by its founders from the outset was to allow the everyday user to resist the dominance of BIG TECH (IBM). Listen to Simon Sinek talk about his experiences giving presentations to Microsoft and Apple. "We buy their products because we believe in what they believe. We don't buy what they make, we buy their products because we identify with their beliefs, and it's these beliefs that dictate their behaviour, and it's WHY we do what we do. People don't buy what we do, they buy WHY we do it." It appears that Tim doesn't share those core values anymore, which is why we buy their products. Like they don't have enough loyal buyers of their products? The solution that fits their origins would be not to price their Studio out of our reach. Being human, we found a way to fight back by re-purposing their old equipment. They made such good products that now they wish they could put them out to pasture. And now they have. Apple doesn't like it when the shoe is on the other foot. I'm thoroughly disappointed in their decision to make my Mac late 2009 obsolete. I purposely upgraded to High Sierra to make it possible to use it as a secondary monitor. I was willing to put up with how overburdened the CPU is now, that every click results in a 5 - 10 sec wait until it figures out what to do. Now I have no secondary monitor and a computer that used to work just fine, but now is a piece of is an opportunity for someone to teach us to take these machines apart and fight back. Sad that they don't appreciate the irony of the situation.

[Jushwa]

We are apple and we care about the environment that's why we don't let you use the displays on our old computers even though they have the capability... What a load of shit.

[Jushwa]

I'm too dumb to figure this one but I hope someone is able to patch in support for this feature eventually.

[celestepalm]

When Apple pulls this sort of crap, it just encourages folks to buy a generic monitor.
Someone can make good $ offering people an affordable work-around for this. Got a 13" Big Sur Air & would love to repurpose my old 2008-9 iMac monitor for it...Thnx.

[tomcunningham]

I use a tool called Luna Display - to connect two 27" iMacs - has worked fine for over a year now....

[hawaiianaf]

Lol. Just got the cables today after I remembered a video I watched last year. That was your video. Man! How quick things get taken away! Oh....

[HildaFyock]

Thanks - got it working with the Cont F2! 2011 Mid iMac and the Macbook Pro 2015!

[jujujustme]

Hi there. I think with Ventura it works again. I have an old 2011 27" imac working as a second monitor. I got the cable and adaptor used on amazon. :)

[theodorepampoukas]

good morning Brad any updates on this ??

[LouisWilsonGluefish]

I am using a 27" 2009 iMac with my M1 Mac Mini. Upgrading the Mini to Monterey still works on this setup. So my Mini has a 24" tv and a 27" iMac as external monitors.

[lilmobop]

I learned this the hardway after cording the thunderbolt & connector. Apple is damn wrong for removing the feature. i think its the worst move they could have made !

[smrotstnerbtube]

Saw another video talking about the F2 issue. He FIXED it by using a PC keyboard to hit the command F2. you may try that and give an update!

[davidweber]

wow I have the same problem when I push Command +F2 with the original Keyboard. I wonder if my thunder bolt cable or something is bad? even though I bought it brand new.

[robsavage]

This only true of the Thunderbolt iMacs ( Non 4K/5K iMac’s from 2011- 2014 ) the 2009/ 2010 27 inch iMac’s can still be used as a monitor and there’s no restriction on which OS you can use. I’ve use my 2015 MacBook Pro running Windows 11, Mojave & Big Sur and all them were able to use the iMac as a display. I was also able to use an old dell laptop running Windows 10 and it was able use the iMac as display too.

[mikeegomez]

Thanks for the info, I tried various plugs and set ups and they don’t work, so now I know why.

[JonTrott]

This isn't true. At least in part. I have a 2011 21.5" iMac running (on a cheap, small external SSD connected via USB) High Sierra. And I have a 2012 MacBook Pro running (with the help of Open Core Legacy Patcher) Ventura. Yes, Ventura. And with the two machines connected via Thunderbolt cable, I can use the Commnd-F2 key and effortlessly use my iMac as a monitor for the Ventura machine. This isn't what Apple says is possible. But it is possible because I am doing it.

[literallymike_]

How else was Apple supposed to sell their $5K monitor with $2K monitor stand? Any mac with a Retina display (2013+...?) won't work. I'm on my way to having a 2015 5K display brick 😢.

[hazyvisuals]

I have it working.. MacBook Pro 2015 mid (Monterey) - LG monitor and 2013 iMac .. While starting up your main machine when you see the loading screen keep pressing cmd+F2 ( on iMac with login screen ) .. The iMac will connect around 30% loading macOS on main machine ..

My problem was: iMac connected but the screen was black.. Now it works almost every time .. Good luck !