my MBP started having problems with playing some movie DVDs (Netflix). Based on some other reviews here, I got this cleaning disk. The first attempt was moderately successful - the disk spun in some noisily fashion and got spat out; no tracks played... Tried the second time and this time it worked perfectly - iTunes was opened and all the tracks available. I went through Intro and Cleaning  track, skipped the tests - my drive works again.