As Raggiemom said check the rethreading especially if you use cheaper thread. It comes unthreaded real easy. That might be why it works for awhile and then you have problems.

I would take it back to the dealer, but get Aurifil thread. I am sure she will be happy with that.

Gutterman seems to work better than Coats and Clark, but not as well as Aurifil.

I know how mad you get when it doesn't work. My service person has one and can use any kind of thread in hers. I just wish Janome would stand behind their product when there is a problem.

It makes me mad I spent good money on this machine and its not working right were taking it to the shop the 16th of feb well see how that goes ill have her get some of that other thread and see how it works.

I have not had a problem with mine either - and as already stated, Aurifil is a much superior thread. It is a wonderful machine - a real workhorse!

It's a great machine and I've sewn many miles with mine since purchasing almost a 1-1/2 yrs ago.

Glad tha tyou have an appointment for it. As mentioned, if you purchased it from the dealer, taking it back, will let them check it out that all is OK. Also, be SURE to take the free lessons. Even if one or both of you have sewn for years, there are little things you can pick up via the lessons.

Thread ... when I was taking my lessons, one of the gals had problems and was told to use Aurifil thread. I was scared ... so just started using Aurifil to ensure my machine was cared for and loved and to hopefully avoid any problems.

Til then I always thought thread was thread, and what difference could there be? Truth be told, , now I absolutely hate and detest using the other threads and Aurifil gives me such a good stitch. Now that I know the machine well, I do sneak back to using other threads only because I want to use it up, but only on not-so-special projects. There's been no problems and it stitches fine, but I sure have noticed the difference in the amount of lint produced ... it just seems to grow.

I just thought of a suggestion ... try stitching off to a pieceof fabric (or use leaders/enders), so that the thread is held in place when you start stitching, to prevent the nests you are experiencing. The other way, is to hold the bobbin and spool threads til the first few stitches are made. I found I needed to do this with my previous machine ... but was shocked to discover it was not required with my 6600. It still haunts me at times ... and old habits die yard, as sometimes I still do it out of that habit!!

I really think that you need to take the machine, some fabric and thread to the dealer. Call and see what might be a good time so that they can spend some time with you. If you end up having to leave it for repair, make sure that when you go to pick it up you take fabric, thread with you and don't leave the shop without sewing on it - for a while not just one seam. That way if it is something in the threading or user error they can help you and if not they can send it back to the repair person.

The bobbin thread can easily slip over to the right, when you see that you will have the thread mess on the bottom of your quilt. I always look at the bobbin and make sure that the thread has clicked in and stays to the left. I like Aurifill and Superior, they both work well. My quilt shop says Coats and Clark will mess up a machine. That use to be my go to thread for 40 years.

I have the 6600. Two things to check, make sure the bobbin is threaded correctly and make sure the thread isn't coming out of the take up lever. You can thread the take up lever from left to right instead of right to left and prevent it from coming out.

so does that help keep it from coming unthreaded

Some threads are worse about coming out of the take up lever than others but threading it backwards keeps all threads from coming out of the take up lever.

I've had my 6600 for over 2 years now and not a single problem ... I love mine ! Best machine I've ever had, and I've owned both Pfaffs and Vikings.
I've had no thread or unthreading problems, but I've always used good quality threads. I've used Gutermann and Mettler, no problems, but I use Aurofil most now and Sulky blendables etc. Don't recommend Coats & Clark thread.

Did you buy it from a dealer ? Your dealer needs to go over it if you're having continued thread problems ...