Minimum Hardware Specifications: At least and 14.3 GB of available storage space to perform the upgrade. How to Create a Bootable macOS High Sierra USB Drive
Apple distributes the OS as an .app installer package. If you specifically need a .dmg (Disk Image) file for virtualization (like VirtualBox or VMware) or archiving, you can convert it using Terminal. Open . Create a blank disk image by running:
Apple provides the full installer for High Sierra through the Mac App Store, though it is hidden from standard searches. download macos high sierra 10.13.6 dmg mac
Once you have your working 10.13.6 installer, back up the DMG to an external hard drive and to cloud storage. Apple will not host these files forever. Treasure that copy—it is the key to keeping your old Mac alive.
Restart your Mac while holding the Option (τ) key and select the USB drive. Minimum Hardware Specifications: At least and 14
If the App Store method fails (common on newer Macs that don't support High Sierra), third-party tools can help you fetch the installer from Apple's servers and package it as a DMG. Microsoft Community Hub
Once the installer app (e.g., Install macOS High Sierra.app ) is saved in your Applications folder, follow these steps: Apple will not host these files forever
If you are unable to download the installer through official channels (e.g., due to Apple's hardware restrictions), community-maintained archives can serve as a valuable resource. These sites have often preserved the original DMG files that Apple no longer hosts directly.