A Microsoft file hosting and synchronization service.
Seems I only got part of your question. But I'll try to answer as best as I can anyway.
There are two basic ways to retrieve a file that is now missing on OneDrive.
- See if you can find it in the recycle bin, and if you see it there, restore it, just like from the recycle bin in the Windows file system. In my case that solution didn't work, as there were so many files in it that it took over a half-hour to simply list them all... and then OneDrive crashed. Apparently it can't handle listing over a half-hours worth of recycle bin files.
- Retrieve them via the 30-day backup feature. That's how I got mine back. A really nice feature of OneDrive is that any file that has been deleted is always available up to 30 days after it has been removed from OneDrive. That retrieval scheme worked for me, thank goodness.
You also could always contact the OneDrive support group via e-mail. But I've had mixed luck doing that. Sometimes they're helpful, and sometimes not. For example, I reported a problem to them back in December (6 months ago), and they promised to look into it and get back to me soon. Still haven't heard from them. I guess "soon", to them, means within a few years.... maybe.
Good luck. OneDrive is a really good Microsoft offering - when it works.