I recently copied some dvds for later viewing. By the time I viewed the movies a week later, I found that the vobs were corrupted. Dvd Decrypter would unsuccessfully try to read until an error was posted. Remembering something I had read previously that high disc rotation sometimes caused a distortion in the disc, I placed the disk into the freezer and allowed it to freeze for about 5 to 10 minutes. I then placed the disc into the player. With a number successive freezing I was able to retrieve the vobs and create a new disc. Hope this may help people retrieve some of their data.