I do not batch convert (intentionally). does that mean my old 10 files could only be opened in 12? That would be insanity for me as I rest easy in the fact I can rely on 10.
I was told by tech support to change the way the file opened in Properties. This was unsuccessful with that file (of course the one I needed to render the most at that moment). I ended up having to send them the file to convert. I suspected the problem lied in the number of layer links, but after reading your other post, it could be my excessive us of plug-in objects.