sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Catalina --nointeraction
hdiutil attach /tmp/Catalina.dmg -noverify -mountpoint /Volumes/Catalina
In this guide, we’ll show you the "better" ways to source this file—ensuring security, speed, and success. Why macOS Catalina 10.15.7?