Hi, I'm using OSX Yosemite, and I'm having trouble getting Mathematica to start after upgrading to the latest version. The previous version of Mathematica ran fine. I just made the upgrade today. By upgrade, I mean that I deleted the Mathematica icon from my Applications folder, and then did a clean install. After I installed it, I tried to open Mathematica by right-clicking the icon and clicking "open". A small bar saying "Verifying Mathematica" opened and ran for about 2 minutes. Then a message saying something like "This application is not recognized and might be dangerous to open" appeared, and there were two buttons: Open and Cancel. I clicked open, and then absolutely nothing happens. I see the Mathematica icon in the bar on the bottom of my screen. There's no black dot under it, the way there usually is when an application is successfully running. However, I did not lock the Mathematica icon to my bar, so the icon shouldn't be there unless it's running. Activity Monitor shows that it is running, but it doesn't say anything about it not responding. If I right click the icon in the botton bar though; it says that Mathematica is not responding. Does anyone know what's going on? Thanks.