I used to have problems with that all the time but not at all lately. I am not sure why. There are a few things I do differently than I used to. I read here to thread the needle on the end you take off first and knot the end coming off the spool last. I use better thread (Superior's Masterpiece 50 weight). I also would stitch hems etc. right to left, now I do the binding stitch away from me to the north. I use to have to always lift up the piece I was working on and drop the thread to untwist. Not anymore. Great.