Apple has officially removed El Capitan from the "Purchased" tab of the App Store. Their support page now redirects to Monterey. So, where do you go?
Enter the command: sudo date 0201010121 (this sets the system date to February 1, 2021). Restart the installer application. Mac Os X El Capitan 10.11.6 Installer Dmg Download
Use this link directly from Apple:
When you shouldn’t use El Capitan
: Click the link above and select "El Capitan 10.11" to download the InstallMacOSX.dmg file (approximately 6.2GB). : Double-click the downloaded file to open it and view the InstallMacOSX.pkg file within. Run Package : Double-click the Apple has officially removed El Capitan from the