Why do DVDs play on one drive and not on another?

I have an external Buffalo Blu-Ray drive (BRXL-PT6U2VB) and successfully played DVDs on it. Recently I bought a set of 5 movies on DVD and the drive refused to recognize any of them. It would spin up and attempt to read from the disc, but the disc would never show up in the file manager, nor did I get the pop-up window asking me what to do with the newly-inserted DVD. Attemptng to open the disc with VLC also failed.

I then tried a different external drive (a Dell DW316) on the same computer, which reads these DVDs with no issue. I get the usual pop-up, choose VLC and the disc will play.

The Buffalo drive will still read other discs (including movie DVDs), just not the ones from the set. All DVDs involved should be Region 2.

OS is Ubuntu MATE 18.04, with the DVD playback components installed.

  • Why do these DVDs work on one drive but not on another? Could this be due to some kind of copy protection (other than DVD-CSS), potentially something that violates DVD standards, causing some drives to reject the disc as being faulty?
  • Are there any workarounds for this (apart from using a different drive)?
  • If not, what should I look for when shopping for a new drive, in order to get one that will read most DVDs, preferably all?