One thing I've learned is to NOT turn the handwheel backwards, it will snarl the thread in the bobbin area. The owners manual says to finish sewing and pull the bobbin thread and top thread to the back and a little left when done with a seam. I had a tendency to do (turn the wheel backwards) this to get the needle to raise before the last stitch is locked...had to break myself of this quickly after locking up the machine two times in one afternoon. Oiling down the area and gently pulling on loose threads released mine.