try using different blank cd-r's some are not rated to burn at 12x speeds, and others may be incompatible with your burner, for incompatibility you simply need to try some different brands out but most generics work fine as long as they are rated for highspeed recording 12x or higher. also ##### what software you are using, what is it's compatibility to your writer and does the software support 12x burn. Burning 12x IS POSSIBLE, I have an aopen 12x10x32 and burn 12x without flaw, I have several friends with the same plextor you have and do not have trouble burning 12x. good luck