A user on Apple Discussions reported that every time they played commercial DVDs they got an
Followed by the DVD Player quitting itself.
When trying to play DVDs on Apple's DVD Player software. Turned out the problem was a certain theme they had installed to use with http://www.unsanity.com/ 's Shapeshifter product. At the point of the writing of this FAQ, it is unknown which themes cause this issue. However, if you get this issue, please report the problem to the theme author and Unsanity so that the problem may be fixed. Always be sure that when you install system modification utilities like these that they are up to date for the operating system you are about to update to before updating to that operating system, and checking how to uninstall them if necessary before updating the operating system.