Hi I have a mid 2010 MB pro 15inch with lion installed. I got a new hard drive Westerndigital 500gb Scorpio blue the same day lion was released and sold my stock drive. Now I had no problems what so ever when I had stock drive and snow leopard but now since upgrading My computer sometimes becomes unresponsive and when listening to music on iTunes the music cuts out as if I'm pressing mute and then unmute in quick succession. I put my friends MacBook 13inch 2007 hard drive into my mac and played her music and it worked flawlessly. The computer was running super quick. I couldn't believe it was my own. I then put my Scorpio blue into her MacBook and I had no problems. After all this I put my Scorpio back into my MacBook pro and once again problems. I have reinstalled lion, from fresh and time machine and still the same. I finally took my mac into apple and they could find no problems but they said the hard drive might be faulty. However as it wasn't stock they couldn't change it. Now I'm thinking are some hard drive just not meant for certain computers because I'm thinking of buying another. Very long post but please can anyone shed some light on the situation.