I've downloaded a copy of the OS X - El Capitan Installer, which I want to make a bootable USB of.

However, it requires you to run the installer on whatever machine you are running, and installs it as an app.

But I cannot run the installer (to create the app) because I am using the computer running macOS Sierra.

It just gives an error "this installer is too old to run on this computer."

  • You can download the installer on any machine, just not the GUI installer. See the dupe for full instructions
    – Allan
    Commented Apr 12, 2020 at 10:46

1 Answer 1


You can use the createinstallmedia command. This link explains: https://support.apple.com/en-us/HT201372

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