sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
Unofficial uploads may not be verified, leading to installation failures mid-way through. macos high sierra 10136 dmg google drive best
Once you have the official installer, the best way to use it is to create a bootable USB. This is much more reliable than trying to run a random DMG file. sudo /Applications/Install\ macOS\ High\ Sierra