Product description DVD DL, Mac OS X 10.11 El Capitan Full OS Install Reinstall Recovery Upgrade These DVDs are NOT produced by Apple. Installing or upgrading your software from a DVD is NOT a quick process and can take 45-60 minutes to complete. Important: During the installation DISCONNECT your Mac machine from Internet. If your Mac isn't compatible with the latest macOS, you might still be able to upgrade to an earlier macOS, such as macOS Catalina, Mojave, High Sierra, Sierra, or El Capitan. 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. OS X El Capitan (10.11) was launched on 25 September 2015, and it is an improved version of OS X Yosemite (10.10). Improved window management, quick and responsive interface, spotlight search, and enhanced graphics were the prerequisites of El Capitan OS. MacOS 10.11 El Capitan - End of Life SCS Computing Support Ended macOS El Capitan no longer supported by Apple. In keeping with Apple's release cycle, macOS 10.11 El Capitan is no longer receiving security updates as of August 2018. El Capitan was replaced by Sierra 10.12, High Sierra 10.13 and the current release, macOS 10.14 Mojave.
Thanks for reaching out to the Apple Support Communities! It sounds like you are having issues reinstalling OS X on your computer and I am more than happy to help! You have tried some really good steps so far and at this point, check out this article with alternate steps to follow for How to reinstall macOS.
For your second question about creating an external installer, I would check out this article with steps for How to create a bootable installer for macOS.
Cheers!
Macos El Capitan
Dec 29, 2017 4:31 PM