With Mac OS X Lion and a new piece of free software, it’s easier than ever to create a USB keychain that you can boot from.

This tutorial shows you how to create a bootable macOS Big Sur USB installer drive, which can be handy for performing fresh installs on your Mac.

The OS X 10.10 Yosemite installer from the Mac App Store in your Applications folder. The installer will delete itself when you install the operating system, but it can be re-downloaded if necessary.

Now that Apple has released OS X 10.9 Mavericks, you might want to consider creating a USB install drive for clean installs and future use.

Once the process is finished, you’ll have a working macOS High Sierra bootable USB install disk that can be used to install macOS High Sierra beta on any Mac that supports it.

If you have an 8GB USB key and you can download the Apple OS X Lion installer from the Mac App Store, you can make your own bootable USB key. It's easier than you might think.

Jesus Vigo shows you how to create bootable USB flash drives that are used to install just about any OS on your computer with the help of Rufus.