I was FMQ the baby quilt I am making for a co-worker, and was actually doing a pretty good job of it. I had no problems, other than an occasional jagged curve or long stitch. Very happy overall compared to my last try on a larger quilt. I finished one half, flipped it around to do the other side. Got almost to the bottom when my bobbin thread ran out. No problem, I wound two in advance just for this. Drop the bobbin in, rethread the needle, and continue where I left off. A couple of inches into my curves, somehow the thread gets caught on the darning foot and everything comes to a complete halt! Not really sure what happened, but the bobbin case is now sitting crooked and there is a bit of a mess. Machine is beeping like crazy. I had to unscrew the needle plate, remove the bobbin case, vacuum and brush out all the lint. Put everything back; needle won't crank up and down. Remove everything again and try again. This time it all seems to work fine. I was able to finish my FMQ without a hitch after that. I really thought I broke my machine! Not sure if it was because the of how my bobbin was, maybe didn't wind correctly, or I didn't drop it in just right? Sure gave me a scare!