@lanodan @sjw @matrix @Moon @coolboymew Was it any Sony DVD before May 2007, though?
ARccOS (Sony DADC's DVD copy protection) had made a revision around the end of April '07 that promised more compatibility.
In fact, most DVDs of movies from that time period that are on sale now presumably seem to be from that later run, since people who bought the first pressings of movies during that period never traded them when Sony Pictures offered by-mail replacements.