How frustrating. I'm giving my machine a time out for tonight. I'll try all these suggestions tomorrow. Hopfully he will behave in the morning after I fool around with my thread and bobbin.

I've also had this happen and what a pain but it seems one time to be the top thread is unwinding to much and then I've also had the bobbin and lint problem but usually it's the top threading. I usually take it all apart and start fresh it seems to help. Good luck it's irritating to keep taking apart especially when you think all is well and discover that mess. Sue

Yep! Just went through the same thing. Tried everything and still a mess. Went to the sewing doc and several phone calls from Doc later...... several things wrong. Need tension readjusted timing redone and something with the needle not centered so fixing that and the last call said I needed a new "hook" what ever that is for $83.?? plus anything else he finds.. Oh and my Ilet button hole stitch only will work in reverse but he did getit to at least work. I was getting
"9's" instead of a circles. But at least it is fixable and I won't have to buy a new machine. Said I should have it back by Wed. I have the Viking 870 Sapphire about 6 yrs old. Have a thread on QB asking if anyone else had had that problem. Hoping cost will be 200.00 or less!!

I have this happen when the thread slips out of the thingy that goes up and down on the front of the machine. The thingy the thread goes into after the tension.

Same thing happened to me. Same machine. Had to bring it in. Used to have my tension on 4.5 know I need it on 7.

That is called a Take-up Lever.

This happens to me when I don't get the bobbin case properly seated.

This happens to me frequently. I completely re-thread the machine from the spool to the needle. I have a really cheap machine so I have to put up with things like this. Sometimes it is just that the thread got wrapped around the needle! Usually if the mess is on the bottom it means the problem is on the top and if the mess is on the top the problem is on the bottom. Good luck. :sew:

Did you have the foot pedal down?

I've had this happen. Once it was because the bobbin area needed to be cleaned, and another time it was a defective bobbin. Both easy fixes.