Hate to be the bearer of bad news, but when you re-format a USB or any other device to work with your console, all content is deleted from the USB. That is why it warns you to save any work or important files somewhere before you proced. (It warns you on
both Xbox 360 and PC).
I can understand you ignored the warnings, alot of people do as you just think it's a dumb message but in this case, it's very important and valid.
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