One time when this happened to me, I even went to a different spool of thread, rethreaded the machine, put in a different bobbin and a new needle. It ended up in the shop and the tech discovered that my bobbin had cracked (Pfaff bought at JoAnn's, not at the dealers which is a no no evidently). With a different bobbin, everything worked fine. He said that sometimes these plastic ones can get a fine crack in them which sure surprised me. I bought 10 new bobbins from the dealer and haven't had the problem since.

Gremlins you say? Must be who took my chocolate bar that's missing since Monday. I swear I put it down in my sewing room and it disappeared.

Gremlins......hmmm....

Glad you were able to get the problem fixed with just a phone call and rethreading machine. Can't wait to see what your quilt looks like.

Try rethreading the machine. Some times it is not the bobbin, but the upper thread. Hope this helps

yes the goblins eat my bobbin thread too.

wow i think those gremlins left my house tuesday night !!!! it didnt matter what i was trying to sew or cut i kept messing up !! i got up on Wed and sat and did the same thing , but with no problem !! so they must of gone to your house that day !!!

ok don't ask how I know but I do . Make sure you put your presser foot down. I have done that more once.
Not fun I know .
Cassie

Always check the take up lever to make sure your thread is in it. This seems to be the number one problem with nests on the underside all of a sudden. I read down the list to find that this may have been your problem too....we have all been here.

Good luck.
D in TX

I don't have a Janome and my Bernina is supposed to be automatic (woudln't have a clue if I could adjust it). I rarely adjusted the bobbin tension on my old Kenmore - usually tweaked the top tension and it worked fine.

That, and try cleaning out UNDER the bobbin case. There may be a little dust (lint) bunny under there. I have a Janome and it's very temporamental when it comes to dust or lint bunnies