Before you download, ensure your Mac can run version 10.12. General requirements include: Late 2009 or newer MacBook Pro: Mid 2010 or newer MacBook Air: Late 2010 or newer iMac: Late 2009 or newer Mac mini: Mid 2010 or newer Mac Pro: Mid 2010 or newer Creating a Bootable USB from the DMG
For advanced users on macOS Catalina or later, you can try fetching the installer using this command: softwareupdate --fetch-full-installer --full-installer-version 10.12.6 . Hardware Compatibility Download Mac Os Sierra 10.12 Dmg
If you use Safari, you can often trigger the download by visiting the hidden macOS Sierra App Store page . This will open the "Software Update" or "App Store" app to download the full installer. Before you download, ensure your Mac can run version 10