Before searching for third-party ISO mirrors, you should always try the official Apple route. Apple still provides DMG files for older operating systems via their support pages.
Ensure the "Install OS X El Capitan" app is in your Applications folder. 2. Use Terminal to Create a Disk Image
You will now have a clean, functional on your desktop. System Requirements for El Capitan
iMac (Mid 2007+), MacBook Air (Late 2008+), MacBook (Late 2008 Aluminum+), Mac Mini (Early 2009+), MacBook Pro (Mid 2007+), Mac Pro (Early 2008+). Memory: At least 2GB of RAM (4GB is highly recommended). Storage: At least 8.8GB of available space.
Once the process is finished, unmount the drive and convert the .cdr file to a .iso file:
Revamped to allow checklists, photos, and sketches.
