I have a 1-year-old MBP (2.4 GHz Core 2 Duo). 95% of the time it's a desktop machine, with a set of JBL Creature speakers plugged into the headphone port. In January I was traveling and tried to play a CD, and got no sound. I checked to make sure the output settings were correct (they were) and just figured my internal speakers were bust. I got home, plugged in my external speakers, and everything was fine, so I promptly forgot about it. Then yesterday I took the MBP outside to work, and when I came in, the oddest thing happened: I plugged my speakers back in, and the sound started coming through my internal speakers. Stranger still, when I unplug the speakers, there's no sound at all! I've done what little troubleshooting I know how to do (I've been blessed with happy Macs through the years): - Problem persists in the Guest Account, so if it's a pref file issue, it's at the system level. - Multiple logouts and restarts haven't worked. - All software and firmware is up to date. This is the craziest thing I've ever seen. Any ideas would be much appreciated!