– Apple previously provided direct links to Sierra via the App Store, but those have been retired. You may still find it through your Purchased tab in the App Store if you had downloaded it before.

This message appears if your current Mac shipped with a newer operating system than macOS Sierra (such as macOS High Sierra, Mojave, or Catalina).

sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ Sierra.app Use code with caution. Press .

Close Disk Utility, select , and follow the on-screen prompts. Troubleshooting Common Errors

: Improved compatibility for Enterprise SMB connections and Xsan client stability.

Disconnect your Mac from the internet. Open Terminal during the installation setup screen and change your system clock back to 2017 by typing date 0715120017 and pressing Enter. Restart the installer. The App Store says "Update Not Found"

: Must be running OS X 10.7.5 or later to perform the upgrade. Supported Mac Models: MacBook / iMac : Late 2009 or newer. MacBook Air / Pro / Mac mini / Mac Pro : 2010 or newer. How to Download the macOS Sierra 10.12.6 DMG File

For a fresh start—such as when selling a Mac or resolving persistent software issues—a clean installation is recommended.