I have also had a lot of trouble with Gutermann thread, but I didn't realise it was the thread that was causing the problems until I bought a new sewing machine. (by the way I did need a new machine). The thread in my sewing machine was getting in a knot and looking as if the tension was not right, although it had been fine until I changed thread and put the Gutermann thread in. After trying all kinds of adjustments I finally decided that my machine had broken completely and went out to buy a new machine. I transferred the thread on to my new machine and filled the bobbin up. I was devastated when my new sewing machine was showing the same symptoms as my old one. I was just about to take it back to the shop when I just thought that as one last try, that I would change the thread on top and in the bobbin. My machine worked perfectly after that! I will not be buying any more Gutermann thread again.