• What OS version is currently installed on your older Mac?
  • What OS version would you like to have on your older Mac after the clean install?
  • What is the specific model of your older Mac?
  • If you intend to recover applications, settings, data to the clean installation on your older Mac, how is that data stored, in a clone? in a Time Machine backup? You don't intend to recover any applications, settings, or data and will stat over with a clean slate?


Believe it or not all of this makes a difference in how to best proceed.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein