iMac 2017 5k host, iMac 2017 21 target display mode

I am using my iMac 2017 5k as my main machine and want to use my 21 inch 2017 iMac in target display mode.

When I try Command + F2 I hear a beep and nothing happens. I have also tried doing it at the login screen and also tried fn + Command + F2 but nothing worked. What am I doing wrong? Is this possible?

Solution 1:

Neither of your Macs support target display mode. Below are the Macs that do.

• iMac (27-inch, Late 2009)
• iMac (27-inch, Mid 2010)
• iMac (Mid 2011-Mid 2014)

For more information see Use your iMac as a display with Target Display Mode.

Solution 2:

I know that I'm three years late, but with MacOS Monterey coming out of beta in a few months, I would like to say that apple re-established such a feature with AirPlay over USB to iMacs 2019 or later. So, not for you personally, but anybody who has a supported mac or iPad (yeah, you can use wireless mode to airplay to your iPad!) can airplay to their device using a USB cable or using wifi (USB cable is faster but still compressed).