I have created boot drives for High Sierra and Sierra before but I do not understand how to create a boot drive for El Capitan on my 2017 iMac. Every time I double click on InstallMacOSX.pkg, it starts the installation and then cancels it because OS X 10.11 is not supported on my computer. Any idea what I can do to create a bootable drive of El Capitan? Thanks so much.
iMac Line (2012 and Later)
While you can download the InstallMacOSX.dmg and open it to the InstallMacOSX.pkg
on any mac, the next stage can only be done on macs that can actually run El Capitan.
So take the InstallMacOSX.pkg and move it over to a mac that is capable of running El Capitan.
Double-click on InstallMacOSX.pkg and the installation window will open.
This installation window does not install El Capitan but creates Install OS X El Capitan.app
in the Applications folder, you use this to make the bootable USB.
Just to confirm you need a mac that is capable of running El Capitan, it doesn't matter if it is running
a newer OS, just as long as it was capable of running El Capitan.
Any mac that came preinstalled with a newer OS than El Capitan will refuse to create the Install OS X El Capitan.app
from the InstallMacOSX.pkg.
While you can download the InstallMacOSX.dmg and open it to the InstallMacOSX.pkg
on any mac, the next stage can only be done on macs that can actually run El Capitan.
So take the InstallMacOSX.pkg and move it over to a mac that is capable of running El Capitan.
Double-click on InstallMacOSX.pkg and the installation window will open.
This installation window does not install El Capitan but creates Install OS X El Capitan.app
in the Applications folder, you use this to make the bootable USB.
Just to confirm you need a mac that is capable of running El Capitan, it doesn't matter if it is running
a newer OS, just as long as it was capable of running El Capitan.
Any mac that came preinstalled with a newer OS than El Capitan will refuse to create the Install OS X El Capitan.app
from the InstallMacOSX.pkg.
How to create an El Capitan boot drive
