Here is how to find a safe image and make it work for your specific setup. 1. Where to Get a Working ISO Apple officially provides El Capitan as a file, not an . If you find a file named macosxelcapitan10111imageiso , it is likely a community-created conversion. Official Source: You can still download the official El Capitan installer from Apple Support. It will download as InstallMacOSX.dmg ISO Alternatives:
Check that the ISO is bootable by mounting it: macosxelcapitan10111imageiso work
The screen flickered. A gray apple appeared, then a loading bar. Here is how to find a safe image
Creating a bootable ISO file for Virtual Machines (VMware/VirtualBox) or archiving. Requirements: A Mac computer (Intel-based) with access to the App Store and Admin privileges. macosxelcapitan10111imageiso work