I am attempting to extend one 27 inch late 2015 imac to another. I got them to connect and the mouse moves between them, but currently both displays are set to "Main display". I want one of them to extend to the other, so I went into settings and changed the Use as to Extended display. The screen faded black for a second and turned back on, and nothing had changed.
[Edited by Moderator]
iMac 27″, macOS 12.6
The Late 2015 iMac cannot serve as a Target Display Mode display for another Mac.
Use your iMac as a display with target display mode - Apple Support
I also don't see the Late 2015 iMac on the "works best with" list for AirPlay to Mac.
System requirements for Continuity features on Apple devices - Apple Support
So how are you trying to display content from one Mac on the other's screen?
The Late 2015 iMac cannot serve as a Target Display Mode display for another Mac.
Use your iMac as a display with target display mode - Apple Support
I also don't see the Late 2015 iMac on the "works best with" list for AirPlay to Mac.
System requirements for Continuity features on Apple devices - Apple Support
So how are you trying to display content from one Mac on the other's screen?
I am wirelessly connecting through displays > add display. If target display mode doesn't work I think that it is not a possibility to do what I want. Thank you!
Cannot set "Use as" to extended display with 2 imacs
