Yesterday Microsoft pushed its seventh Windows 10 cumulative update, KB 3093266. If you run Windows 10 RTM, your system probably rebooted overnight. If you're unlucky, the update didn't install, and it will no doubt try to install itself again in the near future. Such is the nature of forced updates.
The Microsoft Answers forum has several reports. One from RCoover states:
After an apparently successful installation through Windows Update, the computer requests to be booted. During the boot, I get a message that the installation HAS NOT BEEN SUCCESSFUL and then continues to boot. Going into Windows Update Advanced, I find that the update did fail. I did this twice and it failed both times.
In a different thread, LeonardoDV says:
I'm at zero for three attempts on two computers to install this clunky monkey. There were no error codes, just "...couldn't finishing installing...." The last "cumulative update" was just as bad. I have a third computer to try (oh boy, another HUGE download on my slow DSL line). Wanna bet it doesn't work on that one either? Microsoft, on what PCs are you testing these updates? Do you only have three or four test boxes?
There's a long list of attempts to fix the problem -- some successful -- on Reddit.
On tenforums, lopedoggie reports:
This update KB3093266 may cause a recurring update failure (12 in my case) addition to your update history logs or in other words, your pc will enter into a continuous update failure loop while using the win10 auto update feature. There exist a myriad of fixes for this issue on the web and I tried several with no positive results. I was however, able to fix this problem, based on earlier experience with other MS OSs on my PC.
Lopedoggie goes on to offer a possible fix that involves deleting the contents of the C:\Windows\SoftwareDistriution\Downloads folder, followed by erasing the Windows Update history files.
Before going to all this effort, you might ask what does KB 3093266 actually patch? Good question. As usual there's exactly zero worthwhile information in the KB article. A close approximation of what the KB article says is, "We're from Microsoft and we know what's best. Trust us."
However, "MSFT champ" jenmsft -- who appears to be a Microsoft employee posting on Reddit -- says:
This update contains more improvements for anyone who's been seeing issues with start menu reliability or the critical error dialogs mentioning start and/or Cortana - def jump on it if you're one of those impacted.
Team continues to actively investigate other underlying causes for these issues, we appreciate your patience.
That's the closest thing I can find that resembles an official announcement about the contents of the patch.
Ben Oostdam posted a YouTube video about the patch, in which he claims:
It seems to be related to the ESET Smart Security protocols as far as I can see in my archives, but investigations are still running and in progress… It is now definitively related to ESET components, as the update has to be re-installed after installing an additional language pack, as stated and mentioned in the Microsoft KB Article. Be aware that a high technical Microsoft experience is needed to read, and read between the lines of the changed file sizes, and version numbers. so again,..
If you're feeling frustrated, imagine what it's like pushing the cumulative update out on a corporate network, where your job's on the line.
Patching: Windows 10's Achilles' heel.