I have tried for 2 days trying to install ML on my brand new rMBP. It will start downloading for 20 seconds and then stop and show me this error message: The application could not be downloaded. The application you tried to download could not be downloaded. Check your internet connection and try again. (Cancel/Retry) I have a perfect internet connection and was successful at downloading other beefy apps from the app store. I was on the phone with Apple Care for 2 hours yesterday and they were completely stumped. They finally had me download an activity tracker so they can see what the problem is. Anyone else have this same issue?