I installed an SSD in my MacBook and moved the old HD to the DVD bay, which I rarely used. I now have a USB-attached DVD drive. I often rip DVDs I own so that I can watch them when I travel. This creates a dvdmedia file which I could always open in DVD Player, until the DVD drive was removed. If there's no physical DVD drive (the USB-attached one doesn't count) the Player won't load (no DVD player found error, -70012). Is there a workaround to force it to open so that I can read the dvdmedia files?
BTW, VLC is not working for me, either. Long story short, I can use it to play individual chapters, but it won't play the full DVD menu. Thought I'd mention it in case someone was going to suggest it as an alternative.