Use a third-party tool like Mist to automate the download and DMG creation directly from Apple's servers, which is a community-recommended safe alternative to manual Terminal work. 4. Direct Update Downloads (Delta & Combo)
Use the createinstallmedia command in Terminal: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/YourUSBName . How to download and install macOS - Apple Support download mac os high sierra 10136 dmg verified