Hello, I'm in need of a little assistance regarding a USB that has decided to go ape! Basically it was working fine yesterday (on both Mac and PC), but when I inserted it into my MBA this morning the message "The disk you inserted was not readable by this computer." popped up along with buttons reading Initialize, Ignore & Eject. I've tried to 'Run First Aid' to no avail. I am concerned why this could've happened and would really appreciate some advice about what I should do. Kind regards!