It’s not hard at all, and in this article, we will guide you through: It makes sense to create a bootable USB flash drive to install the High Sierra operating system if you want to quickly install it on several Macs without having to download the installer each time. The app will help you delete junk, duplicates, and unnecessary apps in a couple of clicks. MacKeeper allows you to free up necessary gigabytes easily. Please note that before installing any system, you need to ensure there is sufficient space on your Mac.