To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.
If it doesn't, or you don't want to complete the installation at this time, you can come back later and double-click Install OS X El Capitan in your Applications folder. Within the installer, click Continue, agree to the license agreement, and then choose the disk where you want to install El Capitan. Markverhyden said: The Apple ID is the issue. If the machine was registered to an Apple ID, which is% certain, AND they have Find My Mac turned on and they have 2FA then it will not work without that PIN code. As mentioned elsewhere Apple's 2FA is horrible. I created a USB disk with a bootable El Capitan as per this documentation. Plug-in your USB key on a turned-off computer. Start your Mac, press immediately OPTION (aka ALT) Select the Orange icon (aka a USB stick) labelled El Capitan. If it does not detect it after 10 sec and you only see your hard-drive. Try another USB port and wait 10 sec again.
Learn how to upgrade to macOS Big Sur, the latest version of macOS.
Check compatibility
The version of macOS that came with your Mac is the earliest version it can use. For example, if your Mac came with macOS Big Sur, it will not accept installation of macOS Catalina or earlier.
If a macOS can't be used on your Mac, the App Store or installer will let you know. For example, it might say that it's not compatible with this device or is too old to be opened on this version of macOS. To confirm compatibility before downloading, check the minimum hardware requirements:
macOS Catalina 10.15 hardware requirements
macOS Mojave 10.14 hardware requirements
macOS High Sierra 10.13 hardware requirements
macOS Sierra 10.12 hardware requirements
OS X El Capitan 10.11 hardware requirements
OS X Yosemite 10.10 hardware requirements
Download macOS using Safari on your Mac
Safari uses these links to find the old installers in the App Store. After downloading from the App Store, the installer opens automatically.
macOS Catalina 10.15 can upgrade Mojave, High Sierra, Sierra, El Capitan, Yosemite, Mavericks
macOS Mojave 10.14 can upgrade High Sierra, Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
macOS High Sierra 10.13 can upgrade Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
Install El Capitan Without Apple Id Code
Safari downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.
Install Os X El Capitan Without Apple Id
macOS Sierra 10.12 can upgrade El Capitan, Yosemite, Mavericks, Mountain Lion, or Lion
OS X El Capitan 10.11 can upgrade Yosemite, Mavericks, Mountain Lion, Lion, or Snow Leopard
OS X Yosemite 10.10can upgrade Mavericks, Mountain Lion, Lion, or Snow Leopard