No burn is ever error free. That is why they have the buffer under run stuff. Basically the computer feeds the information to drive too fast, and the drive spits it back, and then the computer tries again, etc, etc. That's always the way mine have been. So at the end, it might spit out how many times it had this buffer problem. No big deal. I haven't had a coaster, that wasn't because I screwed it up, in years. It had to be this way, because it is so easy to screw up a burn, and if it screws up once, the disc is trash ( for the most part, there are RW's out there, which allow your to erase the CD and start over ).