I bought my Helix LT last july. Not a single issue with it until last saturday, when it froze in the middle of a gig. Turning off and on again didn't work, as I was getting the : -28 message in the top left corner. Have been trying to make the helix work since then. After so many ons and offs, only one time it started correctly, but froze just after seconds. I don't understand why this problem just appeared, I did not touched anything software-related in months (only little changes of volume, gains, etc.) and only tweaked the exp pedal to be a little bit softer, but i don't think that might be the problem.