I'm not sure if I get the same crackling as you guys. I bought the Ux2 on 2013 and used it on windows. I got the crackling sound on whatever I was recording and in my case I solved it unplugging and re plugging the interface like 2 or up to 4 times until I got rid of it. Now I use it on a Mac and it's still there... It's annoying but I got it solved that way. I don't know if my crackling differs from yours.