Don't know if anyone else is experiencing this but since my upgrade yesterday to ML, my fan seems to be working a lot more. I have opened the Activity Monitor to see what might be causing this and so far, I don't see anything that is causing this. I am not running anything intensive and just wondering is there anything else I should be looking at. Prior to this upgrade, my MBP 13 was quiet, very quiet. Never really heard the fan unless I was in iTunes converting some music and the processor was working hard. Any thoughts would be appreciated.