: Use a USB drive (at least 12GB) and run the createinstallmedia command in Terminal: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume (Replace MyVolume with your USB drive's name) .
If you already possess a macOS High Sierra.dmg file, follow these steps to confirm it is legitimate and uncorrupted. download mac os high sierra 10136 dmg verified
This downloads the verified .app directly from Apple’s CDN. : Use a USB drive (at least 12GB)
: You can access the macOS High Sierra App Store page . Clicking "Get" or "Download" will download the "Install macOS High Sierra.app" directly to your Applications folder. : You can access the macOS High Sierra App Store page
macOS High Sierra 10.13.6 Combo Update (recommended for updating from any previous version of 10.13).
: If you already have High Sierra installed and just need the 10.13.6 point release, you can download the macOS High Sierra 10.13.6 Update directly from Apple Support.