Remember, loops on the back means your top thread tension is too loose or your bobbin tension too tight...loops on the top of the quilt means your top thread tension is too tight or bobbin tension is too loose. Making adjustments...righty tighty, lefty loosey! My advise in either case, try adjusting the top thread tension 1st. Using a practice sandwich 'til you get it fixed is always a great way to keep from having to rip things out.