I use Gutermann all the time (my machine doesn't like anything else). I have had that problem in the past (it's been a few years), at that time thread that was made in Mexico was shipped to the US. So after that bad batch, I have always checked to make sure each spool I pick up doesn't say Mexico on it. Take the spool back to the place you got it, even without your receipt they should replace it. If it's just a bad spool the store won't know much about it, but if it's a bad batch again then they should have been getting returns right and left. Don't be afraid to pull the thread off the spool the look at it, you can always lock it back down. Good luck (at the time of the last bad batches, it came out that the thread Gutermann had made in Mexico would be classed as seconds not the normal qualit).