You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Dual screen problems

Hi, I have just bought a new 27” iMac and am trying to dual screen with my ‘late 2015’ 21.3” iMac. I bought a thunderbolt cable and thunderbolt 3 to 2 adapter. But after connecting the two, clicking ‘command’ And F2, nothing happened. I’ve swapped the ports around, reversed the cable, but it doesn’t show anything to indicate a connection. I phone Apple and after going through the setup. I was first told Big Sur doesn’t support this, which I can’t believe. I was then told my 21.3” Mac is too ‘new’. Again I find this odd. I am returning the cable and adapter to Apple. But would, before I buy another set of cables (I’ve a feeling that one or both could be faulty). Could some confirm whether these two macs can or can’t dual screen please. Thanks

iMac 27″, macOS 11.2

Posted on Feb 10, 2021 11:46 PM

Reply
Question marked as Top-ranking reply

Posted on Feb 10, 2021 11:49 PM

Hi SatnBri,


The 2015 iMac is too new for Target Display Mode. Whatever you do it will not work. Also Big Sur does not support this. Apple was right 100%.


Cheers,


Jack

Similar questions

2 replies

Dual screen problems

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.