What exactly does KB2952664 do?

The most logical reason is the update settings are off that's all,

ThrashZone,

My Windows Update settings are identical to those shown in your post.

Many people have reported that the Windows 10 updates that coerce installation (or nag about installation) appear in their Important list .... while others report that these Windows 10 updates appear in their Optional list. In my case, I have seen these (previously hidden) Windows 10 updates sometimes appear in the Important list, and sometimes appear in the Optional list.

Microsoft has never documented what determines which list these previously hidden updates will appear, and I have not read any user-written post that explains the algorithm used to determine where these previously hidden updates will re-appear.

My point here is that these previously hidden updates can appear in one or the other list.

In whatever list they appear in (after Microsoft has unhidden them), sometimes these previously hidden updates appear checked ... sometimes unchecked. As you know, when they appear checked, then any user that has their Windows Update set to the default value of "Install Updates Automatically" will find Windows 10 being installed.

We can not assume that these (previously hidden) updates will only appear in the Optional list for every user, we cannot assume that these previously hidden updates will only be unchecked, we cannot assume that the end user is computer savvy and has the skills to understand Windows Update settings or Registry settings.

Lets not blame the (computer unsavvy) end user for ending up with Windows 10 on their computer. Microsoft is aware of the large number of computer unsavvy users and is taking advantage of them to meet their Windows 10 installation goals.

You are a cold man, Mr. Thrash.

I love it  :)

It's hard to sympathize with a business or individual that knowingly reserves win-10 or doesn't know how to oversee their business networks :)

But that is your bread and butter so it's all good but in law ignorance is not a defense and it is pretty clear if the person clicks on Accept instead of Decline on the win-10 terms to fully install win-10 it happens.

A couple of firings would help staff messing up systems and productivity in a heart beat ;)

ThrashZone, love your "Kill them all and let god sort them out" attitude but I have to concede the point langware is trying to make.

My colleagues and I support several hundred Windows users (also some MAC and Linux) in the Baltimore/DC Metro area. Most of these are small to medium-sized businesses many of whom have allowed their users to have admin rights on their machines. This is not an ideal scenario and we have done our best to counsel the business owners that this is not, in the long term, in their best interests, but we can only do what we can do. I'm sure you can see where this is leading.

We have been getting calls from clients who are panicking because they have been "upgraded" to Windows 10 and they want to know "what happens next." More often than not we have been able to "UPGRADE" their systems back to Windows 7, though there have been a couple of DOA machines. Worse, several clients have found themselves unable to use business-critical applications because they are not supported in Windows 10.

These are not bad people; the are simply individuals trying to make a living. While I cringe at the thought of so many people using computers who really don't know what they are doing, it is none-the-less the world in which we live. That, and it provides me a means of employment ;).

And before we go saying "if you don't know how to use it don't touch it" remember, if we apply that same logic to everything the number of people with a valid license to operate a motor vehicle will drop by about 60%.

Actually, that might not be a bad idea.

The most logical reason is the update settings are off that's all,