Have questions about booting from the ISO or creating it on Windows/Linux without a Mac? Leave a comment below or check our companion guide: “How to Create macOS El Capitan ISO Using Linux and dmg2img.”
hdiutil attach /tmp/ElCapitan.dmg -noverify -mountpoint /Volumes/ElCapitanInstaller mac-os-x-el-capitan-10-11-1-image-iso
Once you've downloaded the ISO image, follow these steps to install Mac OS X El Capitan 10.11.1: Have questions about booting from the ISO or
After installation, immediately update to 10.11.6 via the combo updater for better stability and security. Search for – but always verify the SHA-1
The Internet Archive holds many legacy OS images. Search for – but always verify the SHA-1 checksum against Apple’s official values (listed in security bulletins from 2015).
If your Mac is running Snow Leopard (v10. 6.8) or later, you can upgrade directly to El Capitan. OS X El Capitan - Technical Specifications - Apple Support
Download Install OS X El Capitan.app from Apple’s server. Once downloaded, close the installer window if it auto-opens. Place the app in your /Applications folder.