To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators should download from Apple, not a locally hosted. Nov 01, 2018 Install El Capitan with USB. In this El Capitan downloading process, if you are going to perform a clean installation method on the startup volume you have to create a bootable USB drive.

I'm a bit confused by your post on what you are trying to do here. Are you trying to boot into Recovery Mode to install macOS to an external USB drive or are you trying to boot from a macOS USB installer to install macOS to the internal drive?

Here are the instructions for creating a bootable macOS USB installer:

Make sure to carefully read the section regarding macOS 10.11 as there are extra steps required to extract the real installer from the downloaded .dmg archive to the Applications folder. After running the .pkg file from the mounted .dmg file you can then proceed to use the command line to create the bootable macOS USB installer itself.

Macs are very picky about the drives used for booting a Mac plus the quality of many USB sticks is extremely poor so try using another USB stick especially a different brand.

When erasing the drive make sure to select the whole physical drive within Disk Utility and erase the physical drive as GUID partition and MacOS Extended (Journaled). The physical drive should be the top most item which is usually identified by the make & model of the drive itself.

El Capitan Dmg

Aug 21, 2021 12:52 PM