A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
Dear Dayna,
Hello! Welcome to the Microsoft Community. I'm glad to be able to assist you. If I misunderstand your question, please let me know promptly.
It looks like after you synced your OneDrive notes with OneNote, only the default notebook is visible, which looks like a lot of notes are lost. I understand the trouble this problem brings to you, and I will try my best to help you solve this problem.
As far as I know, some users reported that there will be compatibility issues between Samsung's photo sync software and OneDrive. If my understanding is correct (other notes are lost). You can check the following content to see if it can alleviate your problem.
Normally, OneNote is synchronized, and you can follow this method, and the notes on your Samsung phone can be synchronized with OneNote. If you find that your notes disappear after logging in with OneNote, try to check your Samsung Notes. It may be because the automatic synchronization function of Samsung Notes has resynchronized your OneNote notes that were synchronized from OneDrive to local storage to other cloud storage. At the same time, if you want, you can also synchronize Samsung Notes and OneNote according to the method in the link below.
Sync a notebook in OneNote - Microsoft Support
If you don't find any OneNote notes, check if the notes you synced to your Samsung phone are still in OneDrive. If they are, you won't lose any data. If not, try the following to get it back:
Try to view and restore your photo files from the Recycle Bin or Version History. If this is not possible and you are a Microsoft 365 subscriber, you can choose to undo all operations on the file in the past 30 days. Get help from the following thread:
Restore your OneDrive files - Microsoft Support
If I understand your question wrongly, please let me know your details in time, and it would be better if you can share some pictures that can express the problem. Thank you in advance for your understanding.
I hope the above information is helpful. If you have any progress or questions, please let me know.
Best Wishes
Pyke.D | Microsoft Community Support Specialist