Apple does not officially provide full installer images in ISO or DMG format on their support site; they only provide
: Use this direct App Store link to find the hidden installer. If your current Mac is too new, the "Get" button may be dimmed. download macos high sierra 1013 iso and dmg upd
Before installing, ensure your hardware or virtual platform meets these core requirements. Minimum Requirement 17A365 (Initial Release) up to 17G66 (Latest 10.13.6) File Size ~5.2 GB to 4.9 GB Processor Intel Core 2 Duo or later Memory (RAM) 2 GB minimum (4 GB recommended) Storage Space 14.3 GB of available storage File System Apple File System (APFS) introduced for SSDs Step 1: How to Download High Sierra via Apple Terminal Apple does not officially provide full installer images