I have a MacBookPro running macOS Sierra 10.12.16 and am using Photoshop CC 2017.1.1
When I try to free transform an object proportionately from the center (Alt+Shift & dragging from corner anchor) it doesn't recognize the command. I do this all the time on my Mac at work without any issues. However on the laptop it does not work. It will only scale as if the "Shift" was pressed.