I think I'm seeing a pattern. I know quite a few people who have been
experiencing the same difficulty with the latest updates that I've had on
two machines. And I know a number who haven't (including my wife). What
seems to differentiate those with trouble and those without is that
machines that were upgraded from earlier versions have problems while
those that shipped with an older version of 10 have not. Both machines of
mine with upgrade failures were upgraded from 7 to 10. Friends who had
versions greater than/equal to 7 are also running into similar trouble. It
is frustrating that the failures are not better understood by MS. I spent
a lot of time with their support folks who finally just gave up.

I was happy to see that MS finally figured out how to update older
versions without requiring a complete reinstallation, but I wonder now if
that improvement had some side effects that now cause issues that I and
others are facing.