Downgrading from Catalina or Mojave to Yosemite (yikes)

[Sharewaredemon]

I have a few questions about downgrading systems that have Catalina/Mojave on them.

I'm helping a friend track down a used Mac for running ProTools, the copy he owns needs to run on a Mac running Yosemite or earlier.

I was under the impression that when you went from High Sierra to Mojave a firmware update gets installed that prevents you from going back to High Sierra, I've done some searching and it seems like people have indeed rolled back from Mojave to HS.

I'm also pretty sure that you can't put an older version of macOS on a Mac than whatever was installed on the unit when it was manufactured.

Does anyone know if that's correct?

Thanks!

 

[chrfr]

I was under the impression that when you went from High Sierra to Mojave a firmware update gets installed that prevents you from going back to High Sierra, I've done some searching and it seems like people have indeed rolled back from Mojave to HS.

I'm also pretty sure that you can't put an older version of macOS on a Mac than whatever was installed on the unit when it was manufactured.

No firmware update from Apple has blocked downgrading the operating system, but you're correct that you can't install an older version of operating system than what was on that model computer when it first shipped.
You need a pretty old computer to get something that's compatible with Yosemite or older.

 

[BrianBaughn]

You can visit everymac.com to get specific answers to which Macs can run Yosemite.

 

[Sharewaredemon]

Thank you!! I'm happy to know I can roll back machines after all.

No firmware update from Apple has blocked downgrading the operating system, but you're correct that you can't install an older version of operating system than what was on that model computer when it first shipped.
You need a pretty old computer to get something that's compatible with Yosemite or older.

You can visit everymac.com to get specific answers to which Macs can run Yosemite.

Ah yes, I know that site, but didn't think of using it to help with the search. Thank you very much!

 

[Fishrrman]

I'd take Brian's suggestion to visit everymac.com to find "the most recent" Mac that can run Yosemite.

Then I'd look for a used one in good condition.
SHOP AND BUY WITH CARE.

Then... I'd wipe the drive clean and put Yosemite onto it.
BUT... be aware that you might have a problem GETTING a Yosemite installer.
If you can't "get one from Apple", there are (cough, choke) "other ways"...

 

[r6mile]

You can get a Yosemite installer (no earlier than that though) straight from the Apple website - https://support.apple.com/en-us/HT211683

Not sure what sort of machine you are after (desktop or laptop etc). But if you are after a desktop, I would recommend a 2012 Mac Mini (which can actually go all the way down to Mountain Lion). You could install Yosemite right alongside Catalina. Otherwise, if you need expandability a 2008 Mac Pro can be had for very cheap (the 2009-12 models can also run Yosemite but sell for a lot more).