I've been using DVD Decrypter and Nero Recode to copy my kids' dvds for several years, simply because kids are kids, and they destroy things! There have always been a handful of movies that DVD Decrypter couldn't complete the decryption process. I've always accepted this as an "Oh well" situation, but recently it seems there are alot more than there used to be. I may be wrong, but this seems to happen more often with the disks that are marked "Rental" at the bottom. I recently bought a bunch of movies from a rental chain that closed down near my house, and most of the disks are stamped "Rental". DVD Decrypter will not work on at least half of them. Is there another program that will do the same job that DVD Decrypter does, that will work on these disks?
You could try DvdFab, there should be a free verison. I dont use it as my computer doesn`t like it. I use AnyDvD and CloneDvD2 from slysoft, Both 21 day free. AnyDvD is a decoder run in back ground and will decode the movie files. Then burn with Clone. You can also burn file to hard drive with AnyDvD, then use DvdShrink (Free) to shrink files if needed. Then burn with ImgBurn (Free). I had pretty good luck with AnyDvD, DvdShrink and ImgBurn.