Find and download a macOS installer file for the version you want to install (sometimes this is a.Check your Mac meets the system requirements to run older OS X versions.To install an older version of OS X on Mac, you need to: In situations like these, installing an old version of the operating system may be your best choice. Or you might have old software that can’t be run on newer OS X versions like Catalina or Big Sur. Older Macs often run better with earlier versions of macOS, for example. And eventually, Apple stops supporting older editions of macOS - and that means no more security patches.īut there are some good reasons to do it anyway. After all, newer versions of the operating system have more features. On the face of it, running old versions of macOS on your Mac seems counterproductive.
