Get Offline Installers for Old Versions of MacOS

Sometimes you get your hands on an Apple computer that is years out of date. Depending on what the system is doing you may need to take incremental steps to update the system to newest version of MacOS. Generally, the process to get Offline Installers for Old Versions of MacOS can be challenging because Apple always wants you to by the latest and greatest. But with a little command line magic that’s no longer an issue.

Problem

By Default the Apple App store wants to jump to the newest version of MacOS.

Solution

Starting in MacOS Catalina 10.15.6 Apple updated the SoftwareUpdate terminal utility to download the installers for supported versions of MacOS. The utility downloads the offline installer to the Applications folder and then it can be copied to the system that needs it.

Get Offline Installer Process

  1. Open the Terminal
  2. Get list of supported MacOS versions
    type: softwareupdate –list-full-installers
  3. Download the Installer (High Sierra Example)
    type: softwareupdate –fetch-full-installer –full-installer-version 10.13.6
  4. Wait for the download to finish
  5. You’re done!
Download MacOS

And if you run into any issues, you can always use –h to open the help screen. Bookmark this blog post so you always have a cheat sheet on how to Get Offline Installers for Old Versions of MacOS.

-Terry