Using Mid-2011 Mac as 2nd Display for Mid-2017 iMac w/Mohave

[Standerson]

I found many posts about this online and in this forum, but not for my configuration, which seems to matter. I want to use a mid-2011 Mac as a 2nd display for my mid-2017 Mac.
• Main Mac: iMac, Mid-2017, Core i5, 27-inch, 3.8, Mohave 10.14.4, Thunderbolt 3 (USB-C)
• 2nd Mac: Mac, Mid-2011, Core i5, 21.5 inch, 2.5, Mavericks 10.9.5, Thunderbolt
• Using a Thunderbolt 2 to Thunderbolt 3 adaptor to connect

Target Display Mode: Does not work with Command +F2. I read somewhere that Target Display Mode does not work with Mohave. If this is true, is there another way to use the mid-2011 as a second monitor for my mid-2017? Do I use Target Display Mode on the 2nd display only or on both Macs? The display option on my main Mac does not recognize the 2nd Mac.

 

[Amethyst1]

I read somewhere that Target Display Mode does not work with Mohave.

This applies to the 2nd Mac, i.e. the one you want to use as a display, not the main one. And you need to press Command-F2 on the 2nd Mac. And ensure the cable used to connect the two Macs (after the TB2-to-TB3 adapter) is a Thunderbolt cable, not a DisplayPort one.

 

[Standerson]

Thank you. Good to know, however, I'm still hoping for information that will help me use my 2nd Mac as a display.

 

[Amethyst1]

You need to press Command-F2 on the 2nd Mac. And ensure the cable used to connect the two Macs (after the TB2-to-TB3 adapter) is a Thunderbolt cable, not a DisplayPort one.

Did you try that? Still no dice?