Downloading the and creating a bootable USB is a straightforward process when you use Apple’s official tools – namely softwareupdate to fetch the installer, followed by createinstallmedia in Terminal.
For newer Macs running Catalina or later, the App Store may block the download. Instead, use Terminal: Mac Os High Sierra Dmg Bootable Usb Download
Difficulty: High. Stick to the createinstallmedia method whenever possible. Downloading the and creating a bootable USB is