Big Sur and Old mac as Second Monitor

[AMH_22]

I have a new MacBookPro M1 with Big Sur and would like to use an old Mac (with OS X Yosemite 10.10 .5 on a 21.5 inch, late 2013, 2.7 GHZ Intel core I5) as the second monitor.

I used to do this successfully with a Mac Book Pro (macOS Catalina version 10.1 5.7 - 2017) by using a Thunderbolt Adaptor to connect the laptop and the old MacBook and then simultaneously pressing Control/Command and F2 on the old Mac. This disabled the old Mac operating and effectively converted it to a second monitor.

So putting in the new M1 MacBook Pro and setting it up exactly the same as I had, pressing Control/Command and F2 on the old mac doesn't do anything to the old Mac and now I just have a MacBook Pro!

There seems to be a lot of discussion about displays with big Sur. I might sound like I'm really adept at all of this but I am seriously not very good at all this tech stuff. If someone could let me know if what I want to do is
1) possible or not,
and if yes
2) provide some instructions in plain language so I can have a shot at this,

that would be really appreciated.

I was really pleased to be able to use the old Mac and know that it wouldn't just go to landfill.
So I think this is a really important thing to solve.

 

[MultiFinder17]

1. Nope. M1 Macs have lost their compatibility with older Target Display Mode iMacs unfortunately. While officially Big Sur doesn't support it at all, even on Intel, I've found that my Intel machines running Big Sur still support connecting to a TDM iMac.

2. Sorry mate

Use your iMac as a display with target display mode - Apple Support

Target display mode is a feature available with certain older Mac models.

support.apple.com

You could always install something like AirServer to set up the older iMac as an AirPlay receiver and use it as an external display that way.

 

[AMH_22]

Thanks so much for the response @MultiFinder17. So frustrating.

Thanks for the information re Airserver. I used to use the second monitor mainly as a second screen (eg zoom on the MacBook and the file I was sharing on zoom on the old Mac). Is that the sort of thing aurserver would allow me to do? It looks reasonably priced but I saw there was Luna display that looks like it Has been developed to specifically address this issue. These don’t seem to be available in Australia at the moment for some reason. But do you have any experience or knowledge of how good that is? Thank you again really appreciate clear response.

 

[MultiFinder17]

I’ve used AirServer in the past, and it does exactly as advertised - it makes your Mac show up as a target to airplay to. I used it on an old iMac for a while to use it as a secondary monitor; given that both computers were hooked up via Ethernet, the speed and quality was pretty good! I’d looked into Luna display before, but it seemed awfully pricey for my needs, especially since the monitor just gets used for mostly static and office type things.

I hope this helps you @AMH_22 !

 

[AMH_22]

I’ve used AirServer in the past, and it does exactly as advertised - it makes your Mac show up as a target to airplay to. I used it on an old iMac for a while to use it as a secondary monitor; given that both computers were hooked up via Ethernet, the speed and quality was pretty good! I’d looked into Luna display before, but it seemed awfully pricey for my needs, especially since the monitor just gets used for mostly static and office type things.

I hope this helps you @AMH_22 !

Thanks for that final bit of information @MultiFinder17. Really helpful. Have a good day.

 

[mdgm]

There's a new feature coming in Mac OS 12 Monterey for using a Mac as a display for another Mac, but both Macs need to be pretty recent: Newer Macs Can Use Another Mac as an External Display on macOS Monterey

Whether unsupported running of Monterey can open up this new feature to working with more Macs would remain to be seen, I guess