A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
Dear Sarah1965,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
As per your description, please don’t worry, we can work together to narrow down and resolve the situation.
It seems that the sync problem is only related with specific OneNote notebook(stored in SharePoint online document library)
To prevent the OneNote notes from losing, before doing any troubleshooting steps, I recommend backing up the affected notebook first.
First, we suggest you connect another WiFior a mobile hotspot to check it again, sometimes your network may affect the sync process.
If the sync problem still persist, try following:
1)Close the affected notebook in OneNote app.
2)Go to OneNote Online, open the notebook in browser first, then click Open in OneNote from ribbon to open it in OneNote desktop client app. See if the error message will disappear.
If the error message still appears and notebook doesn't sync,, since you mentioned, "One of my notebooks will not sync" I suggest you go to OneNote Online create a new notebook, copy and paste all un-synced notebooks in OneNote Online, make sure they all appear in OneNote Online.
(I understand it will spend some time manually copying all un-synced notes to OneNote online, but this will reduce the risk of losing notes. Appreciate your understanding.) then click Open in OneNote from ribbon to open it in OneNote desktop client app. See if the error message will disappear.
If above doesn't help, for further troubleshooting, could you please share information below?
1.Screenshot of error message encountered.
2.Which OneNote applications are you using? OneNote 2016 or OneNote Windows 10 app
3.The version of your OneNote application.
4.Can you recall when this behavior starts e.g., after Office update or Windows OS.
Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!
Sincerely,
Waqas Muhammad