So I have a late 2013 15' Macbook Pro Retina with a 512gb SSD. I just bought a Western Digital 7200rpm hard drive + enclosure today to back up my work and work off of a an external hard drive. Im new to using external drives so this may be a simple solution but here is the problem. 1.)I put the hard drive into the enclosure, screwed it back on, and tried plugging it into the LEFT usb slot on my macbook pro. Nothing happened, so I thought maybe I put it into the enclosure wrong(which scared me because there is only really one way it fits) But I tried the right side of my macbook on that USB slot and the drive powered up so at least I know I didnt break it by installing it into the enclosure wrong. 2.)Now when I plug it into the right side a popup comes up that says "The disk you inserted was not readable by this computer" and it gives me an option to Initialize, Ignore, Or Eject. From this point on I am lost. I clicked initialize but none of that means anything to me. I will also be using this drive on school computers which are PCs. My home system is a mac. So I need to format the drive to work on both. HERE ARE THE QUESTIONs a.)Why is my drive powering on the right side usb but not the left? Will the drive even plug into my USB 3.0 powered USB hub I ordered? b.)How do i proceed from that pop up? c.)Do I need to format it from a PC as exfat so it works better on both of the systems I will be using it on? I think I remember having to do that with an old Western Digital Ultra Passport I was using before. But it wasn't 7200 so I needed a new one.