[tomsem]

OneDrive works great for my use cases, including maintaining backup of my calibre data, for the many years I have used it for that, with painless transition from one computer to another. I have not lost a single file, or had any unrecoverable issue, using any application.

The issue with calibre I related here is a minor inconvenience, not evidence that I'm skating on thin ice.

You offer a very technical argument and I am not qualified to evaluate it. You could be 100% correct, and yet it does not invalidate my experience with OneDrive, and in particular using it with calibre (of which it seems you have little).