softwareupdate --fetch-full-installer --full-installer-version 10.13.6 . The file will download to your Applications Apple Support Method 3: Third-Party Tools (For DMG conversion)

Necessary for installing macOS on VMware or VirtualBox. Offline Installs: Easier to move between computers via USB.

If you are on a newer Mac (like Apple Silicon) that refuses to download older installers through the App Store, you can use an open-source tool like Mist from GitHub . It downloads official firmware and installers directly from Apple's servers. How to Create a Bootable USB Installer