This morning when I opened OneNote 2013 on my development machine I got this warning:
OneNote needs a password to sync

When I tried to click, there is no action... Trying to login again, no result... WTF!

This is a major productivity issue for me, because I work with OneNote on several projects to keep track of essential information like; estimates&budgets, test&review results, technical debt and requirements (in progress).

So I needed a fix fast! After some Googlin' I found a solution to the problem.

  1. Close OneNote and the Send to OneNote panel
  2. Open Windows Control Panel (Windows+Shift+X from desktop)
  3. Go to Accounts \ User accounts and Family safety
  4. Manage Windows credentials
  5. Find all items starting with MicrosoftOffice15_Data:...:
  6. Click remove for all matching items (Microsoft caches your credentials for you notebooks here)
  7. Open OneNote and sign in again:

Voila! Your OneNote books should be syncing again!

PS. This problems seems to be caused by putting your system to sleep while OneNote (or Send To OneNote panel) is still open. I haven't seen this error when hybernating my system though..