Mac Os X Mavericks Download Size There are a few reasons why yous might want to download and install quondam versions of macOS or Mac Os 10. Perchance you are relying on software you have discovered doesn't work properly in the latest version. Or maybe you just don't like the new version of macOS that you accept installed. Another scenario is that yous are a developer and you need to be running multiple versions of macOS and Mac Os 10 so that you lot can be certain that your software runs correctly on them. Either way, you have questions and we have answers. In this commodity we will cover how to get old versions of macOS including Big Sur, Catalina, Mojave, El Capitan, Sierra, Yosemite and even old versions of Mac Os X. We explain how to get hold of the relevant installer files so that you lot tin can install the software on your Mac. We have a carve up article that explains how to install former versions of macOS