I had the same problem until I used it with a "thread bed". It is essentially a small plastic box you place your thread in, and place it next to your machine, then thread your machine as usual using the thread that comes through the top of the box then up through your fist thread guide. It seems to keep the tension just right and because it is encased in the box, it doesn't unravel when you stop sewing. I never use it in the bobbin, but using the thread bed has eliminated the problems for me. Hope this helps.