Users may report that they lose access to a OneNote notebook or a specific OneNote section with the following error:
It can be concerning as retrieving this through the OneNote version history will also present users will the error.
To resolve this, first Open IE and go to the office 365 portal.
Here go to your OneDrive and click the option “return to classic One Drive” from the bottom left.
Select the settings cog located at the top right and select the option to turn on ribbon.
Click on any file, and go to library (located at the top left) Select the option to open in Explorer – this will take you to the local directory of where the files are stored.
Locate the affected NoteBook – in this example it was (My Notebook, Powershell)
Copy the corrupted .one file to your desktop and open it separately.
Right click the newly created section and chose “move or copy”
Move this to the original section, this will create a copy of the section that is now accessible. Once complete simply delete the broken section.