I am currently color grading my first feature film on DaVinci 12.0. I'm on a MacBook Pro Retina 15" with El Capitan.
Last night, my DaVinci crashed, and even though I had my project set on auto-save, my project folder in my Resolve Disk Database completely disappeared. DaVinci either wiped or moved the project folder from the database, and I have no idea why. All other project folders younger and older than the missing project are still there.
I am extremely frustrated. If this project is gone, that means I have lost many weeks of complicated work.
Why did this happen? Why didn't auto-save prevent the project from being lost?
1) you will see a lot of advice on this and other Resolve user support groups, but one primary one is backups are important. When I'm working on a longterm project, at the end of each workday I take time out to export a DRP session file to a separate drive, just in the (very unlikely) possibility that the session goes bad, gets corrupted, or my main scratch drive goes bad. I've had to use these backups maybe 3 or 4 times in 10 years, but it happens.
2) my personal opinion is that laptops are a bad choice for Resolve. BMD has their system requirements on their website, and while some recent laptops can barely handle the software, my experience is that it's slow and sluggish. You're better off using a machine with very fast GPUs and very fast external storage, like a RAID.
3) it's possible the project is still there in the directory but got subtly corrupted in a way that makes it unreadable by Resolve but salvageable in the operating system. I would call BMD telephone support and get them on it ASAP. They're usually very good in emergency situations like this.
4) there's a lot of things you can do to make long-term projects manageable. One I do is, if it's a feature, I generally (but not always) will chop it up into 20-minute reels, just to help save/load times. This also helps in cases where the editor needs to make changes, which affect the conform. Week-to-week, I tend to make more than one copy of the original file, so I might have "Big Movie - Week 1," "Big Movie - Week 2," and "Big Movie - Revised," knowing that we need to work on the most current version. As we throw out old timelines and replace them, I eventually wind up with "Big Movie - Final," which only has the 5 or 6 timelines that make up the final approved movie. When different versions are required (say, a letterbox version vs. a pan/scan version), I'll do another save-as and create "Big Movie - Pan/Scan" or whatever. Same color, different framing. In some cases, certain details change with a 4K delivery vs. an HD delivery, so there might also be "Big Movie 4K."
While Resolve shouldn't ever corrupt projects, bear in mind that sometimes it's the operating system's fault -- not your fault, not my fault, not Resolve's fault... just one of those things. All you can do to ward against it is backup. Take my advice: computers are inherently evil and you can't trust them, not ever. Always check this stuff and take nothing for granted.