Skip this post unless you're having a problem where onenote starts asking for the password to your skydrive account. Solution copied from here.
Onenote is my digital brain, and like my real brain sometimes it gets confused :) For example, twice onenote has said the password to my skydrive account is invalid(*), and refused to allow me to re-enter the password, making onenote effectively useless.
The fix in Windows 8 for when this happens again:
Search -> Settings -> Credentials.
Select - MicrosoftOffice15_Data....
Restart onenote, and you'll now be able to enter your account password.
(*) I think the thing corrupting my credentials is moving time on my machine into the future.