Files disappeared?

[Melohio890]

5 years ago I downloaded a bunch of free cookbooks. Like hundreds. I saved them in my Onedrive in folders by topic, then author. Some I saved under topic, not in an author folder.

It's been awhile since I've opened this folder. Well today I go in and anything under an author folder is gone. Anything just under topic is there. Any idea how this happened? Seems like files outside of the books folder are all there.

[#2]

Multiple questions:
*What platform are you talking about Win10, Win11, Mac, Linux, .?
* Have you logged into OneDrive online to check if they're available there?
* Did you confirm that the files you had years ago were synched?
* Do you keep backups? (OneDrive, Dropbox etc are synced data storage, not really backups)
* Do you have any apps to manage your books (e.g. Calibre) that you've given access to your OneDrive?)
* Have you run a search of your local drives in case they have been moved or otherwise misfiled?