Like pretty much everybody here, I got the magic upgrade (KB3035583) and the little window icon. I didn't go for it right away and it just mostly sat there.

I did download it to one machine, and decided I would wait a while before jumping in on the rest.

Anyhow, I dug out a laptop I hadn't used in a couple of months, intending to just download the upgrades I had missed, just to keep it up to date. After a long while, I had a good handful of upgrades, including the 2+Gb Win10 upgrade. I immediately made it a "hidden" upgrade, selected the upgrades I wanted, and clicked "install".

The first thing it starts to to is download Windows 10. I stopped it, and tried again. No luck - it keeps wanting to install it.

So, off to google. It seems what it's doing is downloading the entire thing so that when you "see the light", you can install it quickly. Thanks a lot.

I went back and uninstalled the magic upgrade, and sure enough the little window icon disappeared. However, it still wants to download Win 10.

I have't had this problem (yet!) with any of my other machines but I think it might be just a matter of time.

Has anyone figured out a (simple) way to prevent it from downloading the OS? I ran into a couple of fixes, including registry hacks and the like, but I was wondering if there were a simpler straightforward way of keeping Microsoft at bay.

If I'm forced, I can just re-install Win 7 and not install the offending upgrade, but I was hoping for a more reasonable solution.