Okay, so you formatted your portable USB HDD to Fat 32, and now it won't recognize it. Did you try using a different cable? I have a WD passport, but it's an older model. Sometimes the the problem can be really simple. Try replacing the cable with another USB mini or micro cable. Whatever your HDD uses. Also try using other usb ports. I don't know why, but my thumb drive doesn't work one of my USB ports. Everything else works on it though.