If you’ve lost some recent notes you were working on, you may still be in luck. OneNote keeps a limited set of automatic backups by default. Where you look for them depends on where your notes are stored.
Search for backups on your computer
If you’re working on notes that were stored on your computer, do the following:
Open the notebook where you lost recent notes.
Click File > Info > Open Backups.
In the Open Backup dialog box, note the folder names that appear. Each folder represents a OneNote notebook that’s stored on your computer.
Double click the notebook folder you want to open.
Select the notebook section backup file you want to open, and then click Open.
If your deleted notes are included in the backup sections or pages, right-click the section tab or individual page tab you want to restore, and then use the Move or Copy command to put the notes back in their original location.
Important: To avoid any confusion between backup notes and your normal notes, be sure to close the backup section when you’re done inspecting it. In the Open Sections view, right-click the section tab of your backup, and then click Close.
Search for backups in a shared notebook
If you’re working on notes that were stored in a shared notebook, do the following:
Open the shared notebook where you lost recent notes.
Click History > Notebook Recycle Bin > Notebook Recycle Bin.
If your deleted notes are found there, right-click the page tab that you want to restore, and then use the Move or Copy command to put the notes back in their original location.
Any notes that were deleted during the past 60 days should appear in the Notebook Recycle Bin, unless the notebook owner or another author emptied the Notebook Recycle Bin during that time.
Important: To avoid any confusion between backup notes and your normal notes, be sure to close the Recycle Bin when you’re done inspecting any available backups. Click the green, upward-pointing arrow next to the Deleted Notes section tab to return to the previous level.
To help protect yourself from future data loss, you can customize the automatic backup settings in OneNote.