I recently bought a 2TB WD My Book for Mac External Hard Drive to upload videos to, but I got a message from my ps4 saying that there wasn't enough space (it said the drive only had 1 GB free). So, I went to my Disk Utility to try to wipe clean the drive (I never uploaded anything to it in the first place), and it won't show up in disk utility. I have a Macbook Pro that's on the OS X Yosemity 10.10.5 update. What can I do to fix this? I barely know anything about technology so help would be great.