I knew you were going to say you were using Masterpiece. I had problems with it also, but for piecing. (I was using a Singer 301 which handles any thread, but I've also had thread issues, not necessarily Superior, on the Horizon 7700.) It is intended for piecing and not FMQ. I talked to the representative at one of the shows and he gave me a new spool, free. Let Superior know what your experience has been, and I'll bet they will help and possibly replace the thread. The rep told me that sometimes there is a bad spool/cone.