I try not to resort to joining a forum just to ask a question, because I can usually fix the problem myself or find the answer. But, I'm all out of ideas and it couldn't hurt to have an account here just incase. After I installed Lion on my mid-2007 Macbook I started having problems with my audio. I Have my Macbook connected to my T.V. through HDMI and the audio hooked to my surround sound system with an Optical Fiber cable with a Mini-Toslink adapter(really awesome) and use it as a media center as well as my everyday computer. But, ever since I installed Lion I have this problem where the audio works fine for a while, maybe and hour or so. But after switch to a few Apps that use audio, Say Plex one minute to watch a show, then iTunes to listen to a song, The Chrome to watch something on Youtube. Sometimes if I were to go back to Plex all of the sudden there would be no audio. If I then turn off my surround sound receiver and turn it back on the sound will be playing as if it would have been, but then if I close plea and open iTunes, I'll have to do the same thing again and reset my receiver. It is QUITE annoying and seems to be a bug in Lion, because it never did this before. I don't THINK it's a Plex problem because it will do it when switching between chrome and iTunes. And If it were a Plex problem, I don't understand why it would affect any other app and wouldn't just be in Plex. The really strange thing is if i restart my laptop it fixes it completely for a while. I can go from app to app and have them all playing audio fine, but after about an hour it will start again. I've tried to look it up to see if anyone else has had this problem and have seem people having problem with headphones and since it uses the same port I thought the fix for that may fix my problem. It says to change from 16 bit to 32 bit in Audio MIDI Setup... But I don't have a 32 bit option... I instead have an option called encoded digital audio, which I suppose is because I'm using an optic cable. But if I select that nothing plays at all even with a reset of computer and/or laptop. If anyone knows anything or has the same problem any help would be greatly appreciated.