I see from other reviews that I am not the only person to experience this difficulty. It arrived. I turned it on. I used it to tune a guitar. It was exactly what I wanted. Twenty-four hours later I wanted to check a D string that sounded flat. Not to worry I thought, and I pushed the button to turn on the tuner and............nothing. Ok I thought, I'll put a new battery in and we should be good to go. Unfortunately, no. As another reviewer mentioned, it was less than 10 bucks so it isn't worth making too big a deal out of it. But, if you are considering this tuner, you may want to re-think your choice. Oh, and D'Addario, we trust you as a provider, supplier, vendor (take your pick here) and this certainly isn't what we expect from you. Even if it is only 10 bucks. Just remember strings are only 10 bucks. Maybe we should we try another brand?