Cannot locate a folder on the Mac Compatible Passport Studio

I plugged my passport studio 2TB to my MacBook Air and was looking through my music folder , when the entire folder suddenly disappeared. The passport still shows that 750GB is used but I cannot find the folder when I plug in the hard disk. The only folder showing is the Mypassport hardware 100MB software. I have tried rebooting the computer, but cannot locate the folder in the Studio disk. 

Hello,

Try it on another computer and use another USB cable if possible.