So my Dad gave us his old Black 13" Macbook for my wife to have a computer to use at home. I wiped it and reloaded Mountain Lion and updated it to 10.7.5. I have iTunes 12.2.2 loaded up and ready to go. When I plug in her iPhone 6S and my iPhone 6 it tells me that the iPhone has given an "invalid response." She has an old iPod classic that connects just fine no issues. Now the iPod is using an Apple connector. The iPhones are using a store bought cord. Could the aftermarket cord be the issue? I remember older Apple products having issues like this back in the day.