I have a 830 too. I am able to use lots of thread but there is a WHOLE box that I bought off an Emb Site that will not work in my machine. Which is a bummer because its all the colors I need. I thought maybe it was just cheap thread but I bought a cone of "good" thread to test at my dealer and it broke too. I have good luck with Coats & Clark and Isacord. And all the old thread that I had for my older machine. Also the thread that I pick up at Hobby Lobby works well. I'm afraid to invest in any other big purchases of thread...The 830's are touchy but when you get "the Feel" its the most amazing machine ever! Don't give up..you won't regret it. Just spend some time getting to know her. =)