the internet is full of error messages about installing KB3000850. To my mind, thats the reason why Microsoft offers a new iso inculding this november update. You can be sure, that winreducer is not responsible for not installing KB3000850.
I downloaded a Windows 8.1 Edition with this update already included. I download all updates (except .NET 3.5) and tools. I did a removal proces in the same way. After installation a few (5 or 6) still appear, but installing these updates is done without any problems. (tested with v1.35 protect Windows Search to keep Windows Store functionality)