What type of needle/size are you using to quilt? Try changing the type of needle to a Microtex or Top Stitch if your machine takes them generally.
The next step is to change out the needle again. Even though you have a new one in now, try changing it. They can have burrs on them or be bent sometimes.
Does your machine have setting preference pages? Check those settings that they are on the default settings. They may have been changed by accident My EMB machine setting was changed for the height of the EMB foot. It caused shredding.
These are suggestions that our LQS tries for customers.
Hope that helps!