Create El Capitan installer thumb drive from Catalina I recently got a 2019 MacBook Pro from work, and a couple of mid 2009 MacBook Pros from a yard sale. I have mostly been using Windows and Linux for the past 20 years.

I'd like to make a El Capitan installer thumb drive, from the 2019 laptop, for the 2009 laptops. I've been following the instructions at https://support.apple.com/en-us/HT201372

When I open the InstallMacOSX.dmg I see the InstallMacOSX.pkg, but when I launch that, I'm told


  This version of OS X 10.11 cannot be installed on this computer.


I had previously tried creating the thumb drive from the one working 2009 laptop but got a similar error.

What could I be doing wrong? What else should I try?
Honsestly I find the easiest way to make a bootable macOS installer is using DiskmakerX.

It is a GUI interface to create pretty much all recent versions of macOS. Just look for the one specifically for the version you want to create.