2011 running SL, I've copied some stuff onto an 8GB SD card and it was fine, until a couple of days later, when I added something else to it, MP3s, and now when I insert it says: The disk inserted was not readable by this computer Initialize - Ignore - Eject I gather Initialising will kill all the work that is on there. Any suggestions? It never asked me to initialise BEFORE I drag and dropped the stuff on there. Is that stuff now lost? I was asked for this format, I've never used it before, always use USB sticks.