Hi there MacRumorians just wanna ask your help of share how do u fix this concern of mind about copy & paste from my macbook pro mountain lion to my external HD i just found it today, when try to transfer my files to my friends external HD, i thought his HD is the problem because my external HD is working since i started to use my macbook pro last week(new), but when i try to transfer my files to my own external HD i discovered just now that is not working anymore, 4hrs ago when it happens to my friends external HD put on my macbook pro same i am experiencing now hope you can give me answer with this.