Last-minute Win10 Anniversary Update patch, 14393.10, may break Cortana

Last night I was surprised — no, shocked — to see Microsoft release a last-minute patch for Windows 10 Anniversary Update, build 1607. Why? Any release of a patch, even a simple patch, on the night before a scheduled massive rollout is begging the Bug Gods to start rumbling.

As of very early Tuesday morning, the Dung Beetles are rolling.

Last night, Microsoft released KB 3176929, the third cumulative update for Windows 10 build 1607. (I call it Win 10.2.3.) As you no doubt know, build 1607 is scheduled to start a massive rollout today, Aug. 2. In the normal course of events, Microsoft would roll out the latest release — the version with all outstanding cumulative updates applied.

Given the problems I’ve seen reported online, it’s likely that somebody in Redmond is reconsidering the decision to roll out 14393.10 this morning.

What does KB 3176929 actually do? We haven’t a clue. There’s no KB article, no Insider Hub post, no Blogging Windows post.

Windows Insider spokesperson Dona Sarkar tweeted last night:

We have now released cumulative update 14393.10 to the Fast Ring via Windows Update … and this is *just* for PC.

Then, four hours later:

14393.10 is now live for Fast, Slow, RP rings. Rel notes coming in FB Hub shortly.

That was around midnight, Aug. 1, the night before build 1607 is scheduled for full release.

Since then, I’ve seen reports of various kinds of anomalous behaviors.

For one, the people who have version 14393 and didn’t acquire it through the Windows Insider program (yes, pirates live among us) also received KB 3176929, and are now sitting at Version 1607 OS Build 14393.10. Clearly, Sarkar’s first tweet was wrong.

More problematic are the reports appearing sporadically about problems with Cortana in this build. On WindowsCentral, poster AB Lambert says:

On my laptop Cortana stopped working … All I have is the search icon which replaced the Cortana icon. I uninstalled the update and got Cortana back and then I reinstalled the update and lost her again.

John McIlhinney says:

This update broke Cortana on my Surface 3.  She’s still there on the Task Bar and she still opens but she can’t do anything. I hope they don’t roll out this release as the Anniversary Update and break Cortana for everyone.

UPDATE: She’s working again.

Over on Reddit, netherbound says:

This update broke Cortana for me. She is not working at all now. Host machine is effected but VM on the host updated just fine and Cortana still works.

And rpodric confirms:

Uh oh, same here with Enterprise (yes, it had been working fine). This is the last thing they needed to happen on Day 0.

That’s precisely the point.

It looks like some Win10 customers are experiencing a last-moment bug — present in 14393.10, but absent from yesterday’s 14393.5 — that disables many of Cortana’s features, including voice response and internet access. With only a few hours of experience under our belts, it’s much too early to pinpoint the exact symptoms or speculate about causes — except it’s clearly linked to this last-minute patch.

I have no idea what possessed The Powers That Be to change a “final” build only hours before it was due to roll out to 370 million-or-so customers.

Are you having problems with Win 10.2.3? Hit me here in the comments, or over on AskWoody.com.

t/h rpodric