Installing from the app itself works, but creating a bootable USB drive ensures a clean, bootable installation tool.
Once your bootable media is prepared, you can initiate a fresh installation of the operating system. Shut down the Mac targeted for installation. Plug the bootable USB drive into an available USB port.
install the OS yet. It extracts the actual installer app into your Applications Locate the Installer : Go to your Applications folder and find the app named Install OS X El Capitan Apple Support Community System Compatibility Mac Os X El Capitan 10.11.6 Installer Dmg Download
1. "This copy of the Install OS X El Capitan application can't be verified"
Yes, you can directly install 10.11.6 over older versions (10.6.8 through 10.10) to bring your Mac up to speed. Conclusion Installing from the app itself works, but creating
Connect a USB drive (at least 16GB) and name it MyVolume using Disk Utility.
You can download the disk image file directly through your web browser using Apple's official server link. InstallMacOSX.dmg Source: Official Apple Support Download Link Mac App Store Route Plug the bootable USB drive into an available USB port
Open the mounted volume window and double-click the installer package inside. Follow the guided software extraction prompts.