Dear Mark,
Thank you for your patience so far.
Since you have already tried most suggestions, and the problem persists, we recommend that you feedback on this issue to OneNote Team. You can open OneNote > select your profile picture in the top left. Then choose Send Feedback, and write this issue.
At the same time, I understand that this is an urgent problem. I sincerely suggest you create a support ticket for this problem. The engineers there have the escalation channels to deal with such problems. They also have the right to view the problems remotely and have more resources to further deal with OneNote problems.
- If you are using a work/school account, you can contact the administrator in your company/school and follow the steps in the article to open a ticket.
- If you are using a personal account, we suggest that you can contact phone support on this page: Contact Microsoft Support.
To not delay your work, as a workaround, we recommend that you can choose to use OneNote for the web to see if it has the problem.
Appreciate your understanding.
Sincerely,
Jazlyn | Microsoft Community Moderator