I have a first generation xtool. I have had few problems before but now it seems to happen often. When using user origin the machine seems to forget its location and skip around a bit. I mark my location clear origin and set new origin. I then frame my work. Sometimes when the laser returns to origin its off location by half an inch or so. Other times it will frame just fine but burn off location. It burned off location 50% of the time on the last project. I had to closely monitor the begining of the burn process to ensure it began in the proper location. Im not 100% sure if this is the xtool or a software issue.