To do so, click on the Apple menu () > About This Mac, then check to see if it has an item labeled “Chip’ (Apple silicon) or “Processor” (Intel processor)
Your computer needs access to the internet if you do not have a local copy of macOS. [2] X Research source
To upgrade your macOS to the most current OS that is compatible with your Mac, press ⌥ Opt+⌘ Cmd+R. For example, a Mac from early 2012 will not be compatible with macOS 10. 15, Catalina. [3] X Research source On an Intel-based Mac, to install the macOS your Mac came with, no matter how out-dated, press ⇧ Shift+⌥ Opt+⌘ Cmd+R. If you didn’t have 10. 12. 14, Sierra, this key combination will not work. If you’ve never installed 10. 12. 14 (Sierra), using ⌘ Cmd+R will install the OS without tying it to your Apple ID. Use this key combination to erase your drive before giving it to someone else. [4] X Research source On an Apple silicon Mac, you can also turn on your Mac and continue to hold the power button until you see the startup options screen. After that, click on the gear icon labelled “Options”. [5] X Research source
If you previously clicked on “Options” in the startup options of your Apple silicon Mac, skip this step.
Do not put your Mac to sleep or close its lid during the installation process. You might see your Mac restart a few times, show a blank screen, and show a few progress bars, but that does not mean installation is done. [8] X Research source
