Happened to mine too. When I left mine alone for 2 to 3 months, it worked again for a couple hours but then it happened again. The pulse gets stuck in a frozen state as I cant change any settings for the time it was outputting sound. So you are pretty much **** out of luck when it comes to USB. Are you using windows or mac? For my case I'm using windows 10. Dont know if this applies to any other OS.