Over time, a lot of cruft, that is, unused extensions, app support files, preferences and other files in your Library folder or System Library folder can become troublesome or even a security issue, like Java. There are some users who suspect that a Clean Install is a good way to approach a complete new version of OS X or macOS. This article, after a brief introduction, will list the steps needed for that Clean Install.
However, there are occasions when a user needs to do what's called a 'Clean Install.' This is like setting up a Mac as if it first came out of the box and then personal data is restored. With this kind of upgrade, all user data, settings and accounts remain as before, and that works for most users most times. Apple has designed OS X/macOS so that one can just upgrade to the next version, 'over the top,' seamlessly.
