After running a migration that contains a OneNote notebook to an Office 365 environment, the migration report shows an error status for the OneNote notebook that contains the detail:
Microsoft's migration API does not currently have a feature to modify OneNote Notebooks to a form that is compatible with SharePoint Online/Office 365.
Note: If you have a large amount on OneNote notebooks, you may want to break up the migration to increase the chances of success.
If you notice that your OneNote notebook is still not migrating properly after following this solution, it is possible the file is corrupted. The best solution at this time is to download it locally to your computer and manually recreate it in the destination of your migration.