<Elephant on the table>
There is no quick fix here folks. If you cannot get this update installed as is, you are facing rebuilds or repairs.
I find it not only laughable, but also disrespectful that the average, or even tech savvy MS
user, would be expected to find a way to trouble shoot this install themselves or completely restore their machine.
I really hope Microsoft comes through with a fix... How embarrassing for a integral update to have so many documented problems.