: Apple doesn't usually provide direct download links for older versions of macOS like Sierra outside of the Mac App Store. If you're looking to reinstall macOS Sierra, using the recovery partition on your Mac (by restarting in recovery mode) can sometimes be a straightforward way to reinstall the version of macOS that shipped with your Mac.
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app Enter your admin password and type to confirm erasing the drive. to ensure your hardware can run Sierra? macOS Sierra (10.12.6) Download - Apple Support Community download macos sierra 1012 dmg file install