Alternative terminal method (faster):

sudo dd if=/path/to/InstallESD.dmg of=/dev/rdisk2 bs=1m

(Replace /dev/rdisk2 with your USB identifier – use diskutil list to find it.)

A real verified High Sierra DMG will have:

We will provide instructions for checking these signatures using Terminal, ensuring your download is safe.

For advanced users who want a .dmg file directly, Apple still hosts the installer package inside a hidden disk image. Use this command in Terminal (macOS 10.15+):

curl -O https://download.developer.apple.com/macOS/HighSierra/Install_macOS_High_Sierra_10.13.6_17G66.dmg

Wait – this link is no longer public as of 2024. Instead, use Apple’s content delivery network with a valid developer seed. For non-developers, the safest official route remains the softwareupdate command, then manually convert the .app to a .dmg (instructions below).

Downloading "macOS High Sierra 10.13.6 DMG" from file-sharing sites (MediaFire, Google Drive, torrents) exposes you to:

The App Store provides an .app file, not a .dmg. To get a DMG (Disk Image) suitable for archiving or sharing offline: