I guess I can get in line behind the lazy ones here on the board, for I have had the very same thing happen to me with one of my FWs, and fiddled and fiddled with the presser foot release, at the same time pulling on my thread until it would come through smoothly (not completely locked in place in the tensioner); and I don't know the specifics of what I did, but it worked, and still does when I use that machine. I just have to remember that it is the one that gives me that problem. Maybe someday, I am too busy today to even go find the machine, let alone try to work out that little problem with it.