This is not a common issue. We can install Melodyne studio on Mac OS X without any issues or error messages. We have not received any other bug reports like yours either.
Anyway, please try the Disk Utility option. Let us know, if you get any further error messages.
And yes, you might want to install Melodyne editor as well, if you need a real plug-in in your DAW or if you’d like to benefit from the additional features (e.g. DNA Direct Note Access) that aren’t in Melodyne studio.
I tried the Disk Utility and Repair option but it made no difference. Then I found my 'old' dmg I'd used on my previous Mac Snow Leopard - it installed right away with no problems!
However that old dmg was 68MB and the new one I couldn't get to install was 88MB.
Now I'm very happy to have my Melodyne back - but.....what am I missing out on???
Another Question: can I install and run both Studio and Editor on the same Mac and then choose which one to use?
Or do I have to choose between the 2 and have only one installed?