This appears to be a pretty common issue, and it seems to be Mac/Apple related. I'm getting quite often some huge blasts of white noise, deafening stuff. Other people are experiencing this while recording audio tracks, but I get this problem on VSL tracks. I'm on Logic 9.1.3, OS 10.6.6 combo updated, IMac 2,66 8Gb RAM. Apple seems to have no solution for this. I'm looking for help because with this problem I can't work anymore.