Hello leopl,
Welcome to Microsoft Community!
As your post is in English, we have moved it to the English section. Thank you for your understanding.
We are aware that you are experiencing issues syncing OneNote. We fully understand the inconvenience this may cause, and the current situation may be frustrating. Before proceeding, we have a few questions that require your confirmation:
The cause of this issue may be that your OneNote on your tablet has not synced to the OneDrive server or the OneDrive server has not synced to your PC. You can log in to Onedrive.live.com to see if your files on the web version of OneDrive can be opened normally. (VPN may be required in some network environments)
Additionally, I would like to inform you that we have recently received reports of OneDrive data sync issues from users in different language communities, which may be related to recent OneDrive server data migration. Thank you for your patience and cooperation. You can provide me with the latest developments on this issue to help us analyze it.
Thank you for your understanding and patience. I hope your problem is solved successfully.
Regards,
Clint| Microsoft Community Support Specialist
