I was happy to see you use the term "take up arm". I didn't know what it was called but I have that prob. ALL the time on my Viking Platinum. It's my biggest complaint with it. Anytime I have a prob. of any kind I've learned to ck. that first. Sure enough, usually the thread has come off. For a machiine this pricey, I sure wouldn't expect that problem.

You may also want to check that the thread isn't catching on anything along its path. I agree with everyone elses ideas as well. Check your bobbin and make sure it is coming out of the smoothly as well.

it may be the thread? when I use a cheaper thread it does that. Also the tension can be moving if it is an older machine even if it is slight.

Didn't read all the replies, but how about a metallic thread needle?

I have a Bernina 830 and was having trouble FMQing with metallic thread. They suggested I use a topstitch or embroidery needle #90. It is much better using the larger eye. Also make sure your thread is on a upright thread holder not horizontal. Thread lubricant also helps. Good luck. :D

Had the same problem with several projects. Changed the needle size so the eye was bigger; problem no longer exists. Hope this helps cause I know it is frustrating.
Diane

I try to use good quality thread, not that 2 for a $1.00 stuff. The cheap stuff can really cause havoc causing a buildup of fuzz inside the working parts of the machine.

I was having the sme problem with varigated thread, and the angels on this quilt board told me to use a needle with a larger eye. I got a metallic needle. Problem soved! I think it's worth a try!! Good luck! :-)

I have had this problem with metalic thread, and I used "Sewer's Aid" it is a liquid in a little bottle you just squeeze a little line down the spool of thread. It seamed to work for me. I had to reapply if I sewed a lot.Hope this works for you.

I have never tried this bu since you say it happens at the end of the spool, what about rewinding the thread on a cone or larger spool. It might tend to relax the thread a bit.
This is just a wild guess and since you are at the end of the project it might be the "fix". And as you rewind to it thru a dryer sheet. These are certainly unconventional suggestions but might work.