Hello, I own an early-2011 Macbook Pro, 15". It is running the latest version of Mavericks. Something's strange with the USB ports– I use a USB hub to connect to my mouse, keyboard, and 2 external HDs. It is a powered USB hub. For some reason, my mouse and keyboard work through the hub, but the external HD's don't show up. I thought it was a problem with the disks, but disk utility doesn't detect the 2 drives– even though the keyboard and mouse are recognized in the hardware diagnosis. The hard drives were working fine until a couple weeks ago. So I unplugged the external hard drives from the hub, and directly connected it to my USB ports on my MBP, but to no avail– disk utility doesn't pick it up. So I tried connecting them to my 2012 Macbook Air (running Mountain Lion)– no problem. THey both show up fine. Could it be a problem with Mavericks? Or has my USB ports been "corrupted" somehow? Help!