See!!! I'm not the only one who's machine has to show her who's really in charge!!! I find that on my BabyLoc if the bobbin isn't wound exactly the machine wants it that day it does the same thing. Sometimes I have to go thru three or four bobbins to get one that she likes. The next day she'll take on that she refused the day before. This even goes for pre-wound bobbins. just make sure to keep the inside of your bobbin enclosure clean and free of little bits of yuck and broken needle tips.