Expert users can use the following sucatalog link to retrieve the required components. Check out gibMacOS for an automated tool.
https://swscan.apple.com/content/catalogs/others/index-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog.gz

To create a bootable macOS High Sierra USB Installer, follow this tutorial:
● How to Make a Bootable macOS High Sierra USB Install Key

MacOS High Sierra General Requirements

● OS X 10.8 or later
● 2GB of memory
● 14.3GB of available storage to perform upgrade
● Some features require an Apple ID
● Some features require a compatible Internet service provider

MacOS High Sierra Hardware Requirements

For details about your Mac model, click the Apple icon at the top left of your screen, choose About This Mac.

These Mac models are compatible with macOS High Sierra:
● MacBook (Late 2009 or newer)
● MacBook Pro (Mid 2010 or newer)
● MacBook Air (Late 2010 or newer)
● Mac mini (Mid 2010 or newer)
● iMac (Late 2009 or newer)
● Mac Pro (Mid 2010 or newer)

Apple recommends you install the latest Mac OS that is compatible with your device. If your Mac doesn't support the very latest operating system, you may still be able to upgrade to a more recent OS. Use software update or find links to download other macOS installers below...

● Where to Download Mac OS X Yosemite
● Where to Download Mac OS X El Capitan
● Where to Download macOS Sierra
● Where to Download macOS Mojave
● Where to Download macOS Catalina
● Where to Download macOS Big Sur
● Where to Download macOS Monterey

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