Hi, I'm not sure if it's feature or bug. While burning a DVD from ISO file I am able to change burning device and burning speed. I don't know if it's correct, but when I tried to change the speed, burning stopped with error. I was burning on 16x speed DVD by speed 4x and tried to change to 16x speed. I use CDburnerXP v 22.214.171.1244 on Win Vista 64-bit with Samsung SH-S183A.