Pretty late but may help someone..I opened Reason 12 stand alone too work some stuff then opened studio One 5 Pro and got a message that "Sound card did not load properly" and so S1 did not play and transport functions would not respond. So after a few hours of trouble shouting via restarting PC Uninstalling reinstalling S1 searching web and Presonus site etc, I tried to load anouther new song and got no midi instrument sound, went to Options/Audio Setup/Audio Device/ tab and found it had been reset to the Windows default sound card so I selected my sound card and all worked. Apparently Studio One's transport play functions will not react if the sound card is not properly allocated. Strange but true at least on my system. Hope this helps someone.