Very strange problem, but very consistent. Doing a short 200 frame animation with three image switch folders, each having from 100-200 frames in them. Anime Studio Pro will just randomly replace them with the dreaded broken image icon, even when rendering. Ugh. It's an HD project, so maybe it's choking, but I've done much larger productions before.
Win Vista 64x 6GB RAM, 8-core processor or whatever that fast one is, RAID array for the files.
Sometimes this happens if your file system isn't in good shape - in that case you should've experienced corrpted images and missing files outside of AS as well.
Did you test wether it's always the same images missing? If not, repeated render to PNG sequence may give you a complete scene over time ... I know this doesn't sound like a good solution.
Nah, not my system or the rendered files, I run a tight ship over here!
Anime Sudio simply chokes on the large files. I rendered the project four times and different files were missing each time, but I was able to combine them into one good movie in After Effects.
Seems the problem is directly connected to switch layers, because I also have 100 images in one project, but just in group layers. No problems during rendering.
I once had a switch file with 16 or so PNGs in it that worked fine for months then started to lose the links. Even after I would relink them they would not be there the next time I opened AS. After about the 3rd time of relinking them they started to stay there when I open AS the next time.