Buffer underrun (whether for a CD or DVD) is caused by not enough memory being available to provide a constant stream of data to the burner. Adding more RAM to your computer will help remedy the problem. Also, not having a lot of extra applications running (these use up available memory) will help. Another thing to try is restarting the computer so as far as memory is concerned, you are starting with a clean slate. (Software, even if you quit it, doesn't always return all of the memory it was using to the available memory.) -Dave -----Original Message----- I've been trying to burn on an eMac superdrive and after a few successes, I've produced several coasters. I got a good DVD from iDVD3, then upgraded to iDVD4 and got another good one. Now I get buffer underrun alerts. I've tried going back to three, but that didn't help and I can't burn in either. Does anyone have any ideas? Thanks, Neil Poese