I had that happen to me for a while and then I figured out that when I thread my machine that I need to just give a little 'tug' on the thread after looping it over that uptake bar and it straightened itself out. It happens to me on my new Pfaff Quilt Expression 4.0. I don't know if that is your problem but it is worth a try. Just re-thread it and give it a tug.