Installing High Sierra in a Virtual Machine (VMware/VirtualBox) requires an ISO or DMG image.
The preference pane will open and begin downloading the "Install macOS High Sierra" application.
Method 2: Trusted Third-Party Archives (For Legacy/Windows Users)
Advanced users can use the command-line tool built into macOS to fetch the exact installer package from Apple's servers. Open the app on your Mac. Paste the following command and hit Enter:
Before downloading the file, verify that your hardware can support macOS High Sierra. Apple designed this operating system to run smoothly on machines dating back to 2009. Supported 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 Minimum Hardware Requirements
OS X Mountain Lion 10.8 or later installed on the target machine How to Download the macOS High Sierra 10.13.6 DMG Safely
Once completed, the file "Install macOS High Sierra.app" will appear in your folder. Method 2: Using the macOS Terminal