How can I revert my iMac to an earlier macOS?

Your Mac can go back as far as Sierra but that's very much not recommended. If you are really set on it, you could go back to Monterey or Big Sur without too much trouble.

However, if it's because you have 32-bit apps you need to run, then you have two options.

1. Keep Ventura but set up a Virtual Machine (you have enough RAM to do this) into which you could install Mojave or High Sierra, to run alongside Ventura
2. Go back to Mojave or even earlier, which is by far the more complex option - see PRP_53's reply.

drjan wrote:

27" iMac 2017

Ventura 13.6.9

40 GB Ram

Why ?

Is there a problem with Ventura 13.6.9 ?

If so, what are the problems

Details and context would help.

Be aware downgrading from Ventura to an older version of macOS is possible but not recommended

It would require Wiping the computer 100% Clean of everything including the Operation System

Then reinstalling the Older Operating System from Scratch, reinstalling all compatible applications and finally adding back all your personal files

Not something I would suggest

Your iMac (Retina 5K, 27-inch, 2017) originally shipped with macOS 10.12.4 (Sierra) or 10.12.5 (Sierra) and can run anything up through the latest release of Ventura.

Ventura is the only operating system that your Mac can run that is one of the "most recent three". Catalina, Big Sur, and Monterey have all fallen out of that list – and have been more or less abandoned by vendors like Microsoft and Adobe. If you go back to Sierra, High Sierra, or Mojave, you'll find that those are so old that they can't even run the current versions of programs like Firefox, LibreOffice, or the Affinity V2 suite.

What do you hope to achieve by downgrading?

Servant of Cats wrote:

If you go back to Sierra, High Sierra, or Mojave, you'll find that those are so old that they can't even run the current versions of programs like Firefox, LibreOffice, or the Affinity V2 suite.

You can run the latest Firefox via FF Dynasty, a GitHub project. The versions of Libre Office that can be run in High Sierra or Mojave give virtually all you need. I don't know enough about Affinity to comment.

christopher rigby1 wrote:

Servant of Cats wrote:

If you go back to Sierra, High Sierra, or Mojave, you'll find that those are so old that they can't even run the current versions of programs like Firefox, LibreOffice, or the Affinity V2 suite.

You can run the latest Firefox via FF Dynasty, a GitHub project. The versions of Libre Office that can be run in High Sierra or Mojave give virtually all you need. I don't know enough about Affinity to comment.

The Affinity v1 products ran on High Sierra – but the current v2 ones require Catalina or better. I do not believe that you can buy the v1 products from Serif any longer, although I could be wrong.

Servant of Cats wrote:

The Affinity v1 products ran on High Sierra – but the current v2 ones require Catalina or better. I do not believe that you can buy the v1 products from Serif any longer, although I could be wrong.

No, you're not wrong. Serif seem to be extremely short-sighted, excluding anyone who either chooses not to run a recent Mac OS, or who cannot, from purchasing their products. After all, v1 was a highly regarded app and Serif had great faith in it, so why they now prevent users from buying it ...

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