Same here on Studio One 4 Professional. I moved to new laptop with Win10 and could not activate melodyne (Essential, that comes with Studio One). No problem, I thought, since I can download installer + activation from melodyne's site (and I have Editor which is better).
Melodyne 64 bit standalone could not be activated. In the end I managed with the 32 bit version but now Studio One crashes upon boot when it reaches "integration with Melodyne".... no answer on the web about this.