Hi @jhuls,

The only documentation I'm aware of is here on Apple's support site: How to reinstall macOS

In short, signing in with an Apple ID (that had "purchased" that OS) was required to reinstall an OS from the recovery partition if you were trying to install a different OS than originally shipped with the computer. Internet recovery would offer up the originally shipped OS as well.

That all changed with Sierra, where an Apple ID isn't required to download and install, or reinstall. If Sierra is already on the computer, it shouldn't prompt for credentials. The linked article above also calls out some newer behavior and modifier keys for machines running 10.12.4 or newer as well.

Hope this helps!

This is becoming less of a thing now as the OS is free, but from this article:

https://support.apple.com/en-nz/HT204904

Apple state "To verify eligibility to install macOS, your Mac serial number is sent to Apple, and you might be asked for your Apple ID."

This is if you are re-installing an OS onto a Mac that didn't originally ship with that OS, you may be asked to enter an Apple ID to confirm eligibility.

Yep,

It's clear as mud, and if you include the macOS beta programs it's even worse.

C

Thanks everyone. Apparently the key word is "might". I hadn't heard that about Sierra so I like the sound of that. We have mostly Yosemite everywhere but will soon be upgrading to Sierra where we can.