DVD's won't play on Mac

This has nothing to do with the Mac being faulty, I had the same issue a few years back and tracked it down to the fact that each CD/DVD player is different and sometimes they just refuse to play certain CDs or DVDs. I remember I burned a few CDs a few years back on one of the Macs, then went to another Mac to install the program. For some reason the other Mac would not read #3, and it would spit it out no matter how many times I inserted it. All discs were same brand, just #3 kept being spit out. Then I decided to burn it once more, this time in a new CD from a different brand and to my surprise it worked. The same disc that was being spit out was read fine in my other Macs, the drive was stubborn and just wouldn't read it. Every now and then I find a disc that wont be read by a certain drive, re-burning it from another computer is probably the best option.

Remember that some CD/DVD players will be more sensitive to read/seek than others, so a CD which will be "worked with" in one player doesn't mean is perfect, it means some players are more tolerant to errors more than certain others. Not because I burned the CD in another Mac meant that it would be worked with in the other, so platform has nothing to do with it.