My project vanished!

I was working on a project today and faced some odd issues. It was the first time I'd used the ulticamera option. Well, finally edited together this hour-long thing and wanted to export... but the "add to render queue" was greyed out and I couldn't do it. Well, I saved the project one last time then shut it, and went to have dinner. I came back to resume trying to sort this out.... I opened the project and... the timeline is EMPTY. I've tried reloading the computer and everything I can think of but it's just gone. I'm baffled. And really frustrated because I want to upload this tomorrow. I'm really afraid that this will happen again, and I don't know what caused it. Is there any way I can find my project so I don't have to spend another day editing it again? Please help!

You messed up.

You did the work in the Multicma clip, which can't be exported. You have to create a timeline and add the Multicam clip to that, then do the work.

I'm not sure I follow. How do you do the editing in the multicam clip? I created the multicam clip, then I dragged it down to the timeline and edited it there. Was it somehow NOT in the timeline...? Actually, one set didn't work because I was unaware that my audio cut out halfway through, so I had to take that apart and do it manually, but the other two multicam clips worked fine. What did I do wrong and what can I do differently? I followed the instructions given by the YouTube video I was using as guidance and it looked just like what he was doing. I was working in my timeline as usual... so how can I tell if I'm just working on the clips or if it's being edited in the actual timeline...?

Also, I did the exact same thing today and rendered the project ASAP without risking quitting Davinci, and all seems good. I still can't figure out where my project went last night though... What should I be sure to do so that this doesn't happen again?

I'm not sure I follow. How do you do the editing in the multicam clip?

I think Jim was referring to the idea that you could've unknowingly opened the Multicam clip (Open in Timeline, etc) and then edited the multiple cameras in the Multicam clip as if it were a timeline. The mechanics are similar, so the major way to differentiate would be: if you were editing the Multicam clip in a timeline, it would appear as a single clip and you choose which camera is displayed from a menu. It doesn't appear as if there were multiple clips (the original cameras) on multiple layers. (At least in Edit. Cut has a different mechanism for multiple cameras. I assume you were using Edit?)

Sometimes people think they need to edit the individual camera clips inside of the Multicam, and that's a problem. At least that's how I understand it. I could be wrong.

I think Jim was referring to the idea that you could've unknowingly opened the Multicam clip (Open in Timeline, etc)

Open in timeline can also happen by accident if you drag a timeline to the track header area

See my bug report here:
viewtopic.php?f=36&t=126323

They did appear as one video and audio in the timeline when I was editing them (except the first one that was messed up thanks to my audio). I've closed and re-opened Davinci with my rebuilt project and it's still there, so that's good....