Help Please... thread in the back looks like a birdsnest
 

I'm trying to free motion,but my thread in the back looks like a birdsnest..Can anyone help?

Could it be the tension in the bobbin holder? I had that problem once and that was where mine was.

What kind of machine are you using? I got results like this when I didn't have my bobbin case properly seated. It appears to be a bobbin tension issue.

Have you checked your bobbin. You might have to rewind the bobbin. Also watch your speed, especially when making curves, you can get what they call eyelashes. There are many very experienced quilters on this site and they might be able to give you some advice. For some reason I can't see the picture you posted so i can't really see what your back looks like. Sorry

As a general rule, if it is on the bottom, it's a bobbin problem...on the top, it's a needle problem. Regardless, I get this when my bobbin is not wound correctly, or if my tension is too loose.

Are you putting your presser foot down?

I had this happen after I placed my folding table too close to my left side which crowded me to the right and resulted in me slightly applying pressure to the knee lift. In other words, the foot pressure wasn't there.

It looks like a bobbin issue. Was it sewing well and then went goofy? It looks ok in your picture on the right. Re-thread the machine, both top and bottom. It wouldn't fix this problem but I use those Bobbin Genies and it has eliminated alot of different issues when FMQ. Do you use these? They make the bobbin spin smoother or something. I don't know exactly what they do but they work. I use them in all my machines.

I can't say for sure what the problem is, but here are the steps I review whenever I have an issue with stitches not forming properly on the bottom:
1) Put in a new needle (should be changed every 8 hours, anyways). Needle should be the recommended size & type that your thread manufacturer recommends (for Aurifil 50/2 thread, I use a #80 quilting needle)
2) Re-thread the top & the bottom according to machine instructions. Be sure to cut thread by spool & pull from by needle. It will pull out any fuzzies that way ... usually.
3) Make sure top & bottom thread are the same unless using monofiliment in the top.
4) Put together a 12x12" quilt sandwich with your scraps & play around with the TOP tension. Probably need to tighten the top tension by 0.5-1 level.

I don't know how many FMQ projects you've done to date. If this is your first, get yourself a yard or two of JAF/HL/Wal-Mart clearance bin fabric. Cut it in half & put whatever batting you normally use in the center. Then spend a few hours practicing. If I really had to guess, I'd guess you're not moving the fabric fast enough through the machine. One thing that's helped me a lot besides practicing has been to draw quilting lines on the fabric. I like using the Crayola Ultra-Clean markers or crayons because I can get a lot of colors that show up well, but you can do it with chalk or the Blue Water Soluble or Frixion pens, too. It's one less thing to distract you from focusing on your speed when doing FMQ. In addition, lighter weight threads tend to be a bit easier to work with than heavier weight threads. So if you're still struggling, cut yourself a break & pick a nice lightweight variegated thread (50/2 aurifil cotton or even a 100wt YLI silk) that matches the background of your quilt.

Best wishes with your project! I love that you did a pieced back!

I can now see the picture and it is definitely a bobbin problem. I would rewind or wind a new bobbin, make sure the bobbin case is clean and practice on some sandwich scraps. If it's not better, check your bobbin case and make any adjustments that are needed.