Mystery update KB 3150513 makes yet another reappearance

On Thursday Microsoft re-re-released KB 3150513, the mystery update that has long raised suspicions among those of us who prefer our Windows snooping to be overt, not covert.

The release doesn’t appear on the Windows Update list or the Windows 10 Update list, but it was pushed onto all Windows PCs in the innocuously titled “Latest compatibility definition update for Windows.”

Microsoft’s description of KB 3150513 hasn’t changed in more than a year:

This update provides the latest set of definitions for compatibility diagnostics that are performed on the system. The updated definitions will help enable Microsoft and its partners to ensure compatibility for all customers who want to install the latest Windows operating system. Installing this update also makes sure that the latest Windows operating system version is correctly offered through Windows Update, based on compatibility results.

Which is enough to get me reaching for my tinfoil hat.

I first wrote about KB 3150513 in April 2015. A similar, not-quite-documented KB 3150513 also made an appearance last May. Not much appears to have changed in the meantime.

Here’s what we know for sure:

• The update includes files called Appraiser.sdb and Appraiser_telemetryrunlist.xml.
• The update was offered on nearly every version of Windows you can name. The KB article lists prerequisites, but there are versions for Windows 10 versions 1607 and 1511; Windows 8 (!) and 8.1; and Windows 7 RTM (!) and SP1. In addition, poster @ch100 documents on AskWoody that a version is available for Windows Server 2016 for the first time.
• When it appeared in September, AskWoody poster K hid the update, but it re-appeared two additional times. At the time, I documented that KB 3150513 had appeared twice, with two different dates: May 4 and May 11, 2016.

Poster @abbodi86 analyzed the update and judged to it be a precursor to upgrading to the Win10 Anniversary Update, which was released last July:

It’s an update for the system’s compatibility database, which is related to the famous scheduled task “Microsoft Compatibility Appraiser”. This diagnostics are required to see if the current machine is applicable for the Anniversary Update (RS1, version 1607) upgrade through Windows Update. Yes, it may send “telemetry” feedback but isn’t the whole of Windows 10 already telemetry-connected?

He goes on to say the following:

Appraiser KB2952664 and the Telemetry DiagTrack program are built into Windows 10 since RTM. Both KB2952664 and KB3150513 are only needed for upgrading to Windows 10; they have nothing useful for current Windows 7 users (well, except providing Microsoft with Appraiser statistics)

Canadian Tech observes:

This utter arrogance and lack of respect, is what drives people to not update at all. Most people I talk to have not allowed Windows to update in a very long time… People are being driven to understand that Windows Update is a bad thing, a risky thing. Most conclude without a great deal of consideration that they’d rather just not risk Microsoft’s malware. The conclusion (albeit without a lot of thought) is that the risk of Microsoft Malware is much greater than the risk of not installing security patches.

And Noel Carboni adds:

It’s been an egregiously bad move by Microsoft to corrupt the integrity of their Windows Update ecosystem by hiding what they’re doing and repurposing it to benefit themselves!

Let’s never forget why there’s a Windows Update process in the first place: They have never delivered software that’s “good enough” out of the box, but with the promise that they’ll fix it later we’ve been willing to buy it.

That doesn’t really fit with it being forced on people, now does it?

As best I can tell, KB 3150513 is only useful for Windows users who want to upgrade immediately to the new Windows 10 Creators Update, which is due in a few weeks.

I’ll have a lot more to say about Creators Update as we get closer to general availability. Suffice it to say that I can’t imagine why anyone—aside from Microsoft employees and cloistered troglodytes—would install Creators Update on day one.

Discussion continues on the AskWoody Lounge.