Sometimes they delete the files and it has to be recreated from scratch. I believe that this is Deep Space Nine’s problem right now.
IIRC someone from the effects team stated most if not all the files still existed, even put out a few sample renders which were beautiful.
That’s good to know. The effects work on that show was very well done. I feel like DS9’s vfx were more quality over quantity whereas a show like Babylon 5 had to take the opposite approach.