Same here. KB3070677 will not install - gets to 67% then reports it failed and says "undoing changes". Tried all the suggestions/fixes listed herein, nothing working. Tried about four times since this weekend.
Perhaps the next version update will get things working. I'm still on build 10130 but in the Fast loop - so I expect a version update soon (unless KB3070677 is the update or is holding things up).
EDIT - Well this KB is to fix an issue where the next version is not being detected. So it looks like the plan to wait for the next update is out.
I'm posting to update this thread - I was able to move onto the next version, but I had to download the Win10 10162 ISO. Then I just clicked on the 10162 "setup" file and the update installed. It did not overwrite any of my personal files or apps.
Since then, Windows updated to 10166 without incident through the normal update process.