Creating Yosemite installer.app from its.dmg File in macOS Catalina

When you open the InstallMacOSX.dmg and get the InstallMacOSX.pkg.

Opening the InstallMacOSX.pkg will open an installer window which creates the Install OS X Yosemite.app.

That part of the procedure can only be done on a mac that is capable of running Yosemite.

A mac that came preinstalled with a newer OS cannot do that part of the procedure.

A really classy move by Apple.

I’ve never heard of a Yosemite disk image produced by Apple. Where did you get it?

Also, there isn’t a way to make an installer from it.

The only thing I can imagine is there is an installer in the image. Just mount it and run the installer app.

For over a year now Yosemite and El Capitan and Sierra all download as an install .dmg

which needs to be opened and processed to create their respective Installer apps.