Information: my PC, an Asus Zenbook Pro, is running Windows 10, Version 1903 (OS compilation 18362.720). OneNote was crashing repeatedly, so I decided to delete the app and reinstall it again. This proved to be a costly mistake as I lost the section where I had all the information, methods and procedure related to my undergraduate thesis. I spent many countless hours working on it... And... Now... It's... Gone... Apparently no other sections in any other notebook were lost, which seems extremely odd. Could someone help me recover it?
What if you access the OneNote via web interface, that should be portal.office.com? Do you see the missing section there? My thought is that maybe there was a replication problem so the changes were newer synchronized properly to the cloud from your local computer.