New iMac 2017 2nd display

[SallyJill]

I bought a new iMac last week, and wanted to use my old one (early 2009) as a 2nd screen but just can't get it working, Apple said my 2009 iMac doesn't have 'Target Display Mode' so they didn't think it's possible. I've tried a cable from thunderbolt 3 to the mini display port but doesn't acknowledge it.
Can it be done any other way?

 

[Slydude]

ScreenRecycler is about the only way I can think of to do what you want. I tried it several years ago and found that it worked but well but the picture on the second screen could drag a bit if you were on a slower network. What are you planning to put on the second screen?

 

[chscag]

Welcome to our forums.

Your early 2009 iMac does not have a video input connection and your 2017 iMac does not support Target Mode, therefore, it's not possible to use your 2009 iMac as a second display. Although, if it's still working, you can use it as a second machine for other things.

I don't believe the application "ScreenRecycler" will be satisfactory for viewing. And to be truthful, if you're going to spend money on that application (it's not free) you may as well buy a second inexpensive monitor to use instead.