Frustrating to have those birds' nests! Lots of good information in this thread...I will be saving it for future reference. Here's what I found out for myself....1) ALWAYS make sure the presser foot is down before starting the machine. 2) if using a DSM, check to see if the machine is threaded properly. For me, the thread once in a great moon slips out of the lever guide, and that causes a messy tangle of thread underneath. 3) both the bobbin thread and top thread should be held in place either by holding them in the back or using a little "leader" piece of cloth first before starting to sew on the project. Hope this helps.