OS installation or downgrade

You cannot install an earlier version of macOS than a Mac was shipped with. And FWIW, the last 15" MacBook Pro was discontinued in November 2019.

popsynic wrote:

But I always thought that you could have older versions on a MacBook, as long as you'd previously downloaded them from the App store and they were associated with your Apple ID?

That's incorrect and has never been true. It is possible to download older versions of an app if you previously downloaded it. It's never been possible to install or even download a version of OS X/macOS older than what a Mac shipped with.

In fact here is an article from apple, explaining how to install and have older and alternative versions of your OS on your MacBook. https://support.apple.com/en-us/HT208891

That article has nothing to do with installing older versions than a Mac can run.

I can see others have said that you cannot install an Apple OS older than what was originally on the Macbook when it was purchased. But I always thought that you could have older versions on a MacBook, as long as you'd previously downloaded them from the App store and they were associated with your Apple ID? In fact here is an article from apple, explaining how to install and have older and alternative versions of your OS on your MacBook. https://support.apple.com/en-us/HT208891

Is this now not correct with the latest Macbooks?

If so, then Surely this would put people off buying a new MacBook, if they needed to say run an older version of OS to make it compatible with an important piece of legacy software they use? And surely it should be up to the user which version of OS they wish to use?

It has nothing to do with MacBooks per se. The simple answer is, hardware advances and there is a point where older versions of OS X/macOS can no longer run on the latest hardware.

Thanks - well never knew that, and I can't understand the logic behind the decision by Apple to lock out owners of Macbooks from installing older versions if they so wish? What's the sense in that?

And do you have any opinion/thoughts on my last point in my post - ....(If so, then Surely this would put people off buying a new MacBook, if they needed to say run an older version of OS to make it compatible with an important piece of legacy software they use? And surely it should be up to the user which version of OS they wish to use?)

Thanks. One additional question for clarity. Does Apple allow an installation/downgrade only to the version that the specific Macbook came with? Or could it be downgraded to the version that this model line originally shipped with? (eg a Macbook Pro 16" will currently be shipped with Big Sur. But this model would have had Catalina on it when this line first came out. So it could run that version - but would I be allowed to go back to that version on a newly purchased model, that came with the latest Big Sur pre-installed).

Very helpful.

Weird isn't it. I have been a Mac user for more than 15 years, and never knew you couldn't go back to older versions of OS than was originally installed on that line. You learn something new every day, as they say. (And it's almost worth keeping one of my older macs, eg. my 2012 iMac, that originally came with Yosemite 'just in case'.).

One more quick question. Do you know if the same is true for running an OS in a virtual environment Can you run an older version of OS in a virtual machine, or even then are you still locked to the earliest version that was shipped with that line of Macbook?

Thanks again for your insight. Really enlightening :)

You can in fact run a OSX guest as a VM that is earlier than your Mac supports. At least it was possible in the past. The problem is of course still downloading an installer earlier than the Mac you want to install the VM on.

To my knowledge you should be able to downgrade to the version of macOS a model was originally released with.