Try performing the following checks:

a. Check that your bobbin tension is set between 250-300 using the tension gauge

b. Check the acti-feed lower limit setting is not set too high or low Default is 4pts

c. Check the retaining finger is set in the correct position using the Help guides in the downloads section

d. If it is a new design make sure the tie in and tie off settings are set correctly.

e. Check that the presser foot is set correctly to the fabric

f. Inspect the drive wheels for thread or grooves make sure they are clean and move freely

g. Change any old needles and make sure they are installed correctly.

h. Run a test design to see if the customer design is causing the issue.

i. Check for sharp areas around the hook and needle plate especially if there has been a recent needle break

j. Check the hook timing