This will be an evolving post but I need to get some of the details down and start collecting data.
I've had over the years, and am seeing more again now an issue with camera RAW images becoming corrupted. More details and links on the full page...
What I think I know about this so far
- I saw it a lot back in 2012 with an older iMac and external Firewire 800 4-disk RAID-5. Per some of the discussion in this thread it seemed to possibly be related to having an external drive that wasn't setup as extended journaled.
- Recently I've seen it a lot on a 5K iMac with an external Tunderbolt RAID-1 drive. Memory is 32GB on the iMac and not memory constrained. I didn't notice any issues prior to moving the images to referenced on the external drive.
- There are reports in OS X, Windows, Aperture, Lightroom
- External media seems to almost always be involved.
- Not all, or even a majority of images are affected.
- In my case I've always been able to pull a good file from an old backup