I’m a new user of Scrivener. So far so good, but today I wrote 3 new chapters and saved them as individual files - the same way I had done for all of the previous chapters. I saved my work. Then saved it again. Then shut down for the day. Tonight I came back and all three files were gone! The folders and all the work just disappeared. Please, before I lose my mind, does anyone know a way to recover these files?
Thanks,
R 
When you say you saved the chapters as individual files, do you mean they were listed as separate documents in the binder, so all part of the same project? Have you tried using the Project Search in the main menu bar to search for some of the text in one of the documents? If they’re subdocuments of a folder that got collapsed, for instance, they might not be visible in the binder but would show up in the search results list. Then you could select the item in the list and choose View > Reveal in Binder to switch back to the normal binder view with that file selected, so you can see exactly where it is.
I’d also make a copy of your project backups, just in case you need to try rescuing anything from there. You can go to the Backup tab of Tools > Options and click “Open backup folder…” to access these, then copy all the backups with the name of the project and paste them into a new folder on your Desktop. The default settings are to keep only the five most recent automatic backups per project, so this is just to make sure your older ones don’t roll off as newer ones are made when you’re checking on the project. You could also temporarily disable the automatic backups in Options while you’re working to resolve the problem, so no new backups are made at all, just don’t forget to turn it back on later.
Another thought–when you saved your work repeatedly, were you just using the regular File > Save or did you use Save As? If the latter, could it be that the project open in Scrivener that’s missing the chapters is an older version rather than your last copy from the night before? You can select “Show full project path in the title bar” in the General tab of Tools > Options, which might help you locate where you’ve been saving projects and whether this is in fact the one you meant to have open.