I saw it on play.com. They have a special offer on season 1 boxsets of a number of TV shows, and I wanted to by x-files season 1, but it said M-Lock and I wanted to make sure what it meant before buying - I don't want to get stuck with a DVD set with some kind of funky new anti-piracy lock or whatever. But I guess it's just a type of DVD packaging. Thanks MeBe.