I've got a Seagate GoFlex Thunderbolt drive I've been using on an Early 2011 MacBook Pro without any problems. Now I'm trying to use it on a Mid-2012 MBP, and nothing happens. The drive appears totally dead when I plug it into the port. Both MacBooks are running the latest El Capitan. And these MacBooks are otherwise virtually identical. So why does the drive work on one and not the other? I thought perhaps it was a bad port on the 2012 MBP, but a quick test with my Thinderbolt to Ethernet adapter suggests the 2012 MBP Thunderbolt port is working fine. And the drive works on other iMacs. So is this a defect of the Thunderbolt port, that it supports the Ethernet adapter but not the drive? Or is there some substantial difference between the Thunderbolt port in the 2011 & 2012 MBP? Or is it something else entirely, like a software or driver issue I'm overlooking?