I'm getting fearful reports about an unannounced and unexpected change in the status of the botched KB 3000850 patch, a massive Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2 rollup that was released out of band in the middle of November. The patch, which caused all sorts of mayhem, was pulled, then reissued as an "optional" update. On March 2 the patch was apparently upgraded to "important," causing many users to wonder what had happened -- and whether they should install it immediately.
The short answer: No.
Here's how Microsoft describes the huge (400MB) KB 3000850 in the KB article:
This November update rollup also includes all previous updates since the previous image update in April 2014. This is a convenient single step to bring Windows clients and servers up to date. Unlike our April update, the November update rollup is not required to be able to continue to receive security or other updates. However, we strongly recommend that you deploy it to Windows clients and servers to benefit from these new features and improvements as well as to prevent many known issues that have been resolved since April. This update is thoroughly tested to the same quality level as our previous service packs.
I count more than 60 patches in the November rollup. When released, it immediately bricked computers running Avast antivirus, and other problems appeared. Avast fixed the problem with its update 141125-1, issued near the end of November.
I can't find any reference to the change from "optional" to "important," but it appears there was no change in the patch itself to warrant the new status. At least, the official Windows Update changelog doesn't mention any change in the patch this year. The KB article doesn't mention any changes, either, although it was updated on March 2, with no explanation given. It's now up to version 11.0.
My take: If you haven't installed it, don't install it yet. There's nothing pressing in the rollup -- no threat to withhold future updates, for example.
Instead, wait for this month's Patch Tuesday release on March 10. At this point, more than 20 separate nonsecurity patches are waiting to be rolled out the Automatic Update chute. Let's see what happens when the smoke clears toward the end of this month and see if any more KB 3000850-specific complaints emerge.