mv /tmp/ElCapitan.cdr ~/Desktop/ElCapitan.iso
Hold Command + R at startup on a Mac that once had El Capitan. Then re-download the installer directly from Apple’s servers. macosxelcapitan10111imageiso work
You now have a bootable ISO for El Capitan 10.11. mv /tmp/ElCapitan
installer into an ISO using Terminal commands on a Mac or third-party tools on Windows Apple Support Community Archival Sites : Pre-made ISOs are sometimes hosted on platforms like the Internet Archive , though these are unofficial Internet Archive Creating a Bootable Installer macosxelcapitan10111imageiso work