For users who need a direct .dmg file to create a bootable USB on Windows or to boot from a raw image, offers a high-speed, verified download of the macOS High Sierra 10.13.6 installer. System Requirements for High Sierra
sudo dd if=/path/to/InstallESD.dmg of=/dev/rdisk2 bs=1m
Use Apple's built-in createinstallmedia tool to extract and copy the verified High Sierra installation files onto your temporary disk image:
The Ultimate Guide to Safely Downloading macOS High Sierra 10.13.6 DMG
Note: If your current Mac is too new (e.g., an Apple Silicon M1/M2/M3 Mac), the App Store may block the download, stating that the OS is incompatible with your hardware. If this happens, you will need to perform the download on an older, Intel-based Mac. Step 2: Create a Verified DMG File via Terminal