Chosen Solution
I’ve a MacBook Pro 15" Unibody (Mid 2012) . The USB ports stopped working a while back; i.e.: the computer would no longer recognize any of USB devices. They are all USB 2.0 devices (external drive, Flash drive, etc.). I did some testing and confirmed that it does indeed not recognize any USB 2.0 devices. the computer works just fine with any USB 3.0 devices that I’ve tested it with. I’ve already tried all the usual quick fixes: reset SMC, reset PRAM, etc. What’s the problem is ? Is it a hardware or software issue?
To test if it is software, start up in Safe Mode by holding down the Shift key on startup. If the USB2 items then work, you have a software issue. This does sound to me like the action of a virus, so I would buy a good anti-virus program like Norton or Symantec Endpoint protection. 70% of the machines I get in are infected. Some, massively.
