That's not all...
Consider yourself lucky, if that's the only parting shot.
On January 15th, despite autoupdate being turned off, the update kindly downloaded itself then, on the next boot, ran to 30% and shutdown the machine. Restarting gave the message "Windows is loading files..." followed by a popup claiming to "repair the startsystem'. Of course, it failed, rebooted, and did the same performance three times before coming up with "Configuring updates etc" and this sequence repeats endlessly.
(It looks like one of the "updates" trashes the thing which calls the loader.)
Solution is, to hit the power switch when you get the "Do not turn off your computer" message, which brings it up in safe mode. You then need to clear the update cache, like this:
net stop wuauserv
rmdir %windir%\softwaredistribution /s /q
net start wuauserv
The machine then works perfectly, until you get the message 'Updates are available etc', and you find that autoupdate has been turned back on, and you can go back to the endless loop described above.
I've put those instructions into a .bat file, which I run every time I shutdown.