My sewing machine guru told me if the thread is bunching on the top it is a bobbin problem, it it bunching on the bottom of the fabric, it's a bobbin problem. That fast check has always fixed the problem for me!

All wonderful advice, our machines are machines that like to be clean and shinny.

Sounds like to me that you top thread has come out of a tention guide. I have had this happen to me before and it took me a long time to figure it out. So now when that happens I rethread everything and check to see if my bobbin was wound correctly. good luck happy quilting yipppie

All good answers from everyone! I recently gave my singer machine to my DIL and told her it was a little quirky and sometimes and did this same thing with the thread so don't get frustrated (she's a non-sewer) and to try these same suggestions. My (mechanic) son called me that night and and proudly announced he fixed the problem and that it was running GREAT! He then told me he found this little screw on the bobbin case that was "loose" so he tighted it up! I gasped in horror imagining how "tight" a mechanic would do a screw. I quickly told him no no no this is not like a car! you may need to loosen it a little!! I laughed about it later.......