This seems to be an issue with C7, at least for my system. Anytime I use Autotune in graphical mode AND use the ‘make curve’ function, C7 becomes unstable and crashes. Otherwise, Autotune works fine in graphical and auto modes with C7. My system is AMD Athlon 64 FX-62 dual core 2.81Ghz, 4G ram, 64 bit Win7, running Cubase 7 32 bit.