A clean InstallESD.dmg for 10.13.6 should have a specific SHA-1 hash (available on Apple’s developer forums).
format. If you need an ISO for a virtual machine (like VirtualBox or VMware), you have two options: Create Your Own: download macos high sierra 1013 iso and dmg upd
Complete Guide to Downloading macOS High Sierra 10.13: ISO and DMG Files A clean InstallESD