Launch your web browser and navigate to the official page for older macOS versions.
Browse and select your downloaded , then click OK to flash it. 4. Step-by-Step Installation Guide
A clean install erases your startup drive completely and installs a fresh copy of macOS High Sierra from scratch.
If you downloaded the .app bundle from Apple using the methods above and specifically need a .dmg file for archiving or virtual machines, you can build one using Terminal: Open . Create a blank disk image by running:
Once you have the Install macOS High Sierra.app :
This report outlines the process of obtaining and installing macOS High Sierra using a disk image (DMG) file. As this OS is no longer available on the official Mac App Store for most modern Apple IDs, alternative methods involving installable DMG packages are required. The process involves creating a bootable USB installer or mounting the DMG directly.
Before initiating the download, ensure your hardware is compatible and your current system is prepared for the transition. Official Hardware Compatibility macOS High Sierra supports the following Mac models: Late 2009 or newer MacBook Air: Late 2010 or newer MacBook Pro: Mid 2010 or newer Mac mini: Mid 2010 or newer iMac: Late 2009 or newer Mac Pro: Mid 2010 or newer System Requirements Memory: Minimum 2 GB of RAM (4 GB or more recommended).
For older Macs, Apple offers disk image (.dmg) files. Double-click the .dmg, then the .pkg inside to place the "Install macOS High Sierra" app in your Applications folder.
: Optimized storage handling in macOS High Sierra allows apps like Mail to use up to 35% less space on your drive. Additional Noteworthy Features