This kind of error has been cropping up here for years. It used to be something that could be reliably reproduced by trying to import tagged MP3 files, but I do not recall ever seeing any other cause isolated. I have never even been able to figure out from reports whether this is a Windows system error or a Cakewalk application error when the message is generated. Since this message indicates "audio disk" full, I assume it comes from Sonar, since windows would have no way of knowing what Sonar is using the disk for. Deleting the picture cash was offered as a solution. Does Sonar put a limit on the size of the picture cache on disk?