I upgraded to AutoTune 7.5.3 x64, running on Window 7 X64
OS fully patched, Cubase updated to 7.02 x64
Everytime I load Autotune it crashes Cubase.
Please note, I also happen to have Autotune live, which works fine (but 32 bit)
I can happily run AutoTune 7.5.3 x64 on Cubase 6.5 x64