Imac (Late 2012) as a second screen

[racreis]

Hi, I have an Imac 2012 (Late) 27inch and want to use it as a second screen with an 2020 imac 27inch. It just will not connect as a second screen.

I have plugged in a 2005 imac 27inch in to the 2020 imac 27inch and this works fine.

With a bit of research I found its because my 2012 imac has been upgraded past High Siera.

Anyone expienced this? I dont have time machine on. Is there a way to revert back ti High Siera or run the OS from a USB drive?

Thanks R

 

[MacsBug]

For this, I use a Lunadisplay (https://astropad.com/product/lunadisplay). You would plug the luna display int your 2020 iMac and then just run the secondary software on the 2012 iMac.

 

[racreis]

For this, I use a Lunadisplay (https://astropad.com/product/lunadisplay). You would plug the luna display int your 2020 iMac and then just run the secondary software on the 2012 iMac.

OMG, This would perfectly. Thanks for this. Life saver WOOP WOOP!