You can obtain the installer directly from Apple using a compatible Mac:
softwareupdate --fetch-full-installer --full-installer-version 10.13.6 Use code with caution.
When you boot from the USB and get the error, do this:
Press . Terminal will stream the complete installer directly from Apple's content delivery network (CDN) into your Applications folder. How to Convert the Installer App to a DMG File
: A free tool that downloads full macOS installers directly from Apple. You can select 10.13.6 and export it as a Internet Archive : For virtual machines or legacy hardware, you can find a macOS 10.13 ISO/DMG mirrors, but verify the checksums if possible. Terminal Command : On a compatible Mac, you can try: