So I went to the Mac App Store downloaded DP 4 and it downloaded flawlessly. Then I clicked the app icon and selected my main HDD (which is currently running DP 2). Every loaded good and it asked me to restart my computer I did that. Then, it brings me to another install window everything goes well for about 5 minutes and then it tells me it can't install and to trying restarting my computer and to try again. I have tried re-downloading Preview 4 from Mac App Store and it doesn't seem to work. Anyone have this problem? Anyone have solutions to this problems?