The macOS High Sierra 10.13 DMG file is not officially available for download from Apple either. However, you can download the macOS High Sierra 10.13 installer from the Mac App Store and then create a DMG file from it. Here's how:
For the average user, the safest way to get High Sierra is directly from Apple.
If the App Store method fails (common on newer Macs), these tools can fetch the files directly from Apple's servers: : A Mac utility available on
If you cannot access the Mac App Store—perhaps because your current Mac is "too new" to download older software or you are on a PC—many users turn to archived direct links.