I simply don't know... I'm a novice at best, and only discovered the joy of using command line frequently late last year. I know more than the average user and love customizing my system directly from the registry, but I lack the internal technical knowledge of how windows operates.
What I do know however is KB2919355 issues have plagued both users with and without prior issues in Windows. Why is a very good question... and I think it probably does have to do a lot with Ms. Bradley's hypothesis that it's affecting those users who upgraded to Windows 8 from a prior OS, especially since these issues aren't being replicated on machines running server editions of windows. Not all users fall into this group, but a significant portion probably do. Those that don't may fall into the category of accidental or forced shutdown of windows without realizing Windows Update was running in the background. This is more than likely what caused my issue with installing KB2919355.