Its not realllly an answeer, but Ihad taahe same problem with MM17 Premium download.  Inst. Package would start to download and then stop.  After a re-boot and new connection, the package would start and then lock up my PC.  This happened several times so I finally gave up and contacted Tech support. 

They have decided to send me a CD withh the program.  I had problems with MM16 Premium but Tech support worked wiht me and we got it running, thats why I took a chance on MM17.  Sometimes I think the program is way to flexible and has to many whistles and bells.  Seems to me you gotta start small, record 2 or 3 tracks for 16 bars, save it, play it back....if all that works, slowly start manipulating the data, always remembering where you were and what you were trying to do.  Good luck