Hello Oleah. Are the backups that are missing data Scrivener’s automatic backups? Or, were they backups that you created manually using the File > Back Up commands?
Were your backups stored on your PC’s hard drive? Or, were they stored to a cloud server or external hard drive? And, were the backups compressed into ZIP files or stored uncompressed?
Does your PC use any kind of file-management utilities or programs? If so, does that utility or program have access to the location where those backup files are stored?
If these were Scrivener’s automatic backups that it compresses into ZIP files, then I would be surprised that their contents were lost like this. Section 5.2.3 of the Scrivener manual discusses safely accessing its automatic backups, and you can access the manual via Scrivener’s Help menu.
If they are backup copies that you made using the File > Back Up commands, it’s possible that you didn’t have them compressed. That might make them vulnerable to an overly zealous file-management utility, a cloud-syncing service’s “online-only” storage settings, an incomplete sync, or even a failing hard drive.
Although, to be fair, even Scrivener’s automatic backups can fall victim to a bad hard drive, syncing errors with cloud servers, and other mishaps.
No system is 100% foolproof, which is why I frequently refer users to my colleague’s “Got a backup?” post.
Having a few different recovery options is often the wiser approach, particularly with work that cannot be easily recreated.