I use this machine at work and love it. If using a cotton thread in the machine I do have to lower the tension to about a 3 and thread thru the last two holes on the pre-tensioner. When thread cutting, I leave the presser foot down, hit the cutter button and make sure the thread cutter is totally finished before removing my piece. I think it is because of the natural stretch of the cotton thread. If using poly thread I still leave the tension around 3 but thread thru all 3 holes on the pre-tensioner. Also, clean out the tension disks. I use unwaxed dental tape. I use about a 1 yard piece of dental tape and tie knots about every two inches in the tape. I wrap this around the tension disks and "floss" back and forth. This removes a bunch of gunk. Hope this helps.