I am using a MacBook Pro and have an external hard drive that I use to store my images on. It has worked fine for quite a while and now all of a sudden it does not show up on my desktop, in the finder or in the disk utility when I plug it in.
I have tried both USB ports and they work fine with other devices. When I plug the HD into my PC laptop it recognizes the drive even though nothing shows up because its formated to Mac only.
What happened? How can I get it back?

