well this has been extremely frustrating but I believe I've resolved my issue. I had this error popping up a billion times: Error message 0x80070652; i was ready to smash my laptop.
i went into startup manager and disabled "EVERYTHING" except for my graphics (nvidia) and dropbox, restarted the computer and when i ran the update it finally went through. what must have been happening, one of the things running in startup, either adobe updater, or Microsoft office uploader was preventing the 8.1 update from starting. hopefully this resolves your problems as well.
I have a Sony VAIO Tap 11. I updated essentially out of the box (only added a mouse). The first time I tried the Windows 8.1 upgrade I rec'd a 0xC1900101 - 0x2000C. I did all the windows updates, all the VAIO updates, more windows updates, more VAIO updates (until there were no more to do).
Then I would get 0xC1900101 - 0x40019, over and over again when attempting to upgrade to 8.1.
Then I did the following
- Same as above quoted suggestion, I disabled everything in the Startup Manager (the Startup tab in the Task Manager for those looking for it). Note that "Kaspersky Anti-Virus" refused to Disable, so I left it alone.
- Reading other's suggestions regarding peripherals I turned off the Tap 11 VAIO keyboard and the Logitech Ultrathin Touch Mouse (t630). This left nothing connected but power.
The upgrade succeeded. Not sure if I needed to do both of the above, no going back now.
hth