When trying to activate the device generates a unique ID from the hardware and send's it off to MS Activation servers. I'm going to gloss over the install steps as other people have already mentioned this, but just in terms of licensing Windows 10 licensing is the same system as older devices with a tweak that once it's activated once you don't need the key again to re-activate.

I'm assuming that to be legal, we should still wipe it and install 10 Pro on it since that's how it was originally purchased as, but I'm just curious why it activated with Enterprise and if we'd actually be OK to just leave enterprise on there. I don't fully know how Windows 10 activation work these days since we don't have to use keys but it pulls from BIOS or somewhere but does anyone know why this worked?

However, the laptop activated even though it's not connected to our corporate network (it's on our guest network). It reset Windows but left it as Enterprise instead of Pro since that's what it had on it. Today, as a test, I used the built in Reset setting within Windows to see what would happen. To do this we install Windows 10 Pro from a flash drive and everything is good. At that point, we like to reimage the laptops back to a plain Windows load and let someone use them as a personal laptop. Then, after they are 3-4 years old, we replace them with new ones. Once we get them, we reimage them to Windows 10 Enterprise, add them to our domain and go from there. We order laptops with Dell and they come with Windows 10 Pro.

Factory reset dell laptop