If you’ve ever had a OneNote notebook that suddenly disappeared on you, this might be a way to get it back. Not guaranteed, but something that you may not have thought to look.
2. This will open a folder similar to this one. Note: your version number may vary.
3. Open the folder and look for a folder named Backup.
4. Inside the Backup folder, there may be some OneNote notebooks. If you find the one you’re missing, you can breathe a sigh of relief.