Life would be so much simpler if Microsoft would tell us what it's trying to put on our PCs. Earlier this week the mystery patch KB 3035583 was unveiled by German site heise.de as a shill for Windows 10. The patch is all about advertising Windows 10 and upgrading to Windows 10, from Windows 7 and 8.1 PCs. Now readers report the patch is marked as "Important" and installs by default through Automatic Update.
I think the description of the patch by rugk on the eset Security Forum is accurate: It's "an adware/PUA/PUS/PUP for Windows 10 upgrade." But to reiterate, we haven't seen any examples of the advertising. We don't know what the final behavior of this patch will be -- it could be as innocuous as an occasional balloon notification that a free upgrade to Windows 10 awaits or as obnoxious as the botched "not genuine" screen blackouts. This is the plumbing, laid well in advance of Windows 10's availability.
When I posted that blog, on my PCs, the patch was offered through Automatic Update, but it was marked Optional and it was unchecked -- even if you have Automatic Update turned on, the patch wouldn't install unless you went into the teeming mess and checked this specific patch, giving your OK for installation.
Now, I'm seeing a bunch of mail and posts from people who swear the patch is marked as Important and it's checked, which means that if you turn on Automatic Update (not recommended), or if you casually, manually install all Important patches, you're going to get this one. On my PCs at the moment, the Windows 8.1 PCs have KB 3035583 marked as Important while my Windows 7 PCs still have it as Optional.
Others report that their Windows 7 PCs have KB 3035583 marked as Important. I have no idea why.
The patch itself is unchanged from when it was first released on March 27, according to the KB article. To date, we only have Microsoft's official description: "This update enables additional capabilities for Windows Update notifications when new updates are available to the user. It applies to a computer that is running Windows 8.1 or Windows 7 Service Pack 1 (SP1)" -- disingenuous at best.