I have experienced the same thing at least 100 times over the past five years with my 300E. I have had it in the shop over and over again. The answer I got from my dealer is that I am having problems because I use my machine. The bobbin case has been replaced twice. It is very frustrating. I have found the bobbin is a common problem with Janomes after reading many, many reviews. I will never purchase a Janome again. Wish I could help you. It does take out the fun of embroidering.