I recently turned my 2009 mac mini into a mediacenter. It appears that about one in five of my dvds will not even mount. I suppose this has to do with some copy protection. Same goes for my music CDs.
I would be willing to buy an external drive - but I'm worried that in the end it will have the same issue (and I won't be able return a "functional" drive). And so far I don't know which "feature" will be required to play all DVDs.
Web search only gave me info on failing drives that won't read any media. But as I can reliably read some media I don't think these apply to my case.
I hope someone can shed some light on this issue.
Some additional info
About the mac mini - in the course of turning it into a media center I did a fresh install of mountain lion with latest updates. The only additional software installed is XBMC and VLC. So I doubt this might be a software issue.
Before that I hardly used the drive. I think I only used it like a dozen times. Also didn't burn any disk.
DVDs won't open in the Mac DVD player software and not even mount as data disc.