Apple distributes the OS as an .app bundle rather than a raw .dmg file. If you need a true DMG file for virtualization or archiving, you can convert the downloaded app using the native Terminal app.
Apple no longer provides regular security updates for High Sierra. If you use this OS on a daily basis and connect to the internet, be aware of the potential security risks. Consider using it only for offline tasks, legacy software, or inside a carefully configured virtual machine. macos high sierra 10136 dmg
macOS High Sierra (version 10.13.6) was the final major release of the macOS High Sierra operating system, released by Apple Inc. in July 2018. The (Disk Image) file for this version is a critical archive format used primarily for creating bootable install media, downgrading operating systems, or installing the OS on multiple Macs without re-downloading the installer. Apple distributes the OS as an
Many professional audio and video plugins that broke in the transition to 64-bit-only Catalina still run perfectly on High Sierra. If you use this OS on a daily
Finding this file today is akin to finding a pristine physical disk. It allows users to create bootable USB drives to revive "dead" Macs. Without this specific DMG, a 2011 MacBook Pro that has had its drive replaced cannot be easily restored to its last supported operating System.
High-performance graphics technology that laid the groundwork for VR and machine learning on Mac. How to Create a Bootable USB from a DMG
A solid‑state drive (SSD) is strongly recommended, as High Sierra’s APFS file system is optimized for flash storage.