The problem? Apple’s official download links have been buried, broken, or redirected to newer macOS versions. Worse, many third-party websites host corrupted or malware-infested DMG files.
| Test | Expected result | |------|----------------| | Mount DMG | No mount error. Contains .app or InstallMacOSX.pkg | | Verify signature | codesign -vvv Install\ OS\ X\ El\ Capitan.app → should pass | | Create bootable USB | createinstallmedia works without “expired” message after date set back | | Installation | No “This copy of the Install OS X El Capitan application is damaged” error | mac os x el capitan 10116 installer dmg download fixed
Before installing macOS El Capitan 10.11.6, ensure your Mac meets the system requirements: The problem