Problems with NEC 6500A


I am new to copying dvds. I have installed the latest DVD shrink, clone DVD, DVD decrypter , and DVDFAb, Also Any DVD. I am facing a problem with 50% of the dvds that I am trying to copy:
1- I don’t manage to see some of the dvds. When I go to the DVD drive i find 0 objects, clone DVD tells me the DVD is not in a valid video format.
2- I still receive redundancy check message for some of th2 DVDs.

Any help and guidance is appreciated to have the optimal way to copy dvds?

Welcome to the forum.

Are the discs your having problems with, pressed DVD movies?