TeresaA

This can also happen when the thread isn't feeding properly, actually when it's caught up and the machine sort of over-compensates by pulling harder.

But yeah, the thread most likely got out of the tension disks somehow.

Snooze2978

Usually when that happens for me I know my thread has jumped out of the uptake lever. It happens quite a lot too and I don't know why it jumps out. Otherwise I have no clue but I can sympathize with you during the frogging.

Suz

Sometimes, it is best to turn off the machine and start up again. The machine will reset and then you can go thru the check points, if there are any.

Since the thread nest is on the bottom side, I suspect something is wrong with the upper tension. Start here when checking.

jlm5419

Yes, this is the answer. Been there, done that. ☺

katsbmr

i had this happen last week. Took out my bobbin, and bobbin case only to find a very large bundle of dust. After cleaning, it was fixed

joogoo

It is not usually the bobbin but the thread is not through the tension disks. If the problem is on the bottom of the fabric the problem is on the top and visa versa.
Judy

newbee3

it is the top thread probably in the tension area is not threaded right

BettyGee

Has happened to me. I take everything out; bobbin and clean the area and replace it carefully, re-thread with a new needle and this has always corrected the "bird's nest." It is a royal pain to clean up the mess, but it will happen again and you'll know just what to do.

MargeD

I've had this happen to me when the thread has somehow come out of the threading "whatever" on my machine. Usually, if I rethread the machine, check the bobbin for any extra lint, and if so clean out the lint on my machine and that generally works well. As much as I hate to say it, it happens to all of us, but you will have to rip the stitches out, as you will not have a seam that will hold up.

grandme26

Change your needle and rewind your bobbin.