I am soooo sorry that you are having this problem. You are not alone, if you check the Janome yahoo group or sewingpatternsreview, you will see there are many in this boat. I bought my Horizon 7700 three and a half years ago, when it was brand new, and have had tons of problems...two new motherboards, the same bobbin nonsense, another "E4" error whenever I use the thread cutter, self threader broke, single hole plate also caused E4 or E5 errors, so don't use that anymore, tension craziness, trouble with the bobbin winding properly...and it has been in the shop so many times, a long drive and two week wait....and all I can get is "operator error" from the dealer (I have been sewing for almost 50 years). I spoke with the Janome guy at the Houston quilt show and he suggested I contact the district sales manager, only problem is how to find out who that is???? No way is the dealer going to tell me! At this point I am ready to cut my loses and buy a new (NOT Janome) machine. I realize this is not much help, but at least you know that it isn't you!!!