Dear Mark,
Greetings! Thank you for posting in Microsoft Community.
As per your description, you cannot export your notebook, you get error message "Sorry we can't create |0 It's possible you don't have the right permissions or disk space".
We appreciate you share with us the troubleshooting steps you have tried. For the situation you encountered, we do understand the inconvenience caused and apologize for it.
We'd like to help you, please let us cooperate, we can work together to narrow down the situation.
Since you can export other notebooks, it seems like issue only happens to the specific notebook.
May I know if you export notebook from File>Export>select Notebook, then OneNote Package(*.onepkg)?
To narrow down the issue, if you try to export each of your notebook section from File>Export>select Section, does same error message still appear?
To better help you, we'd like to collect following information:
1.Is the notebook saved in OneDrive for business or personal OneDrive?
2.We didn't reproduce the error message when testing in OneNote. Could you share with us your OneNote version? We'd like to test in same version as yours.
Please go to File>Account, capture a screenshot of Product Information, as shown below.
Thanks for your time and cooperation! We hope you stay safe and healthy always.
Sincerely,
Tina | Microsoft Community Moderator