ok, I have been searching all over the net. I cant seem to get any where with this. Posted on the "official" Apple support form a couple weeks ago, no answers. I have a 2009 mac pro, with 10.7.5, been trying to upgrade to 10.8. I down load the program from app store. I click to install, and choose my main hard drive. It runs a little bit, then says its restarting. And thats it. Once it goes to restart, I get the Apple Logo, with the spinning cog. It will stay that way for a min or so, then the Apple logo turns into a circle with a slash through it. I have to hard rest, boot into safe mode, and remove the OSX installer file, so that my computer will boot back correctly. Ive tried this many different ways. Ive created an osx installer thumb drive, and tried to do a fresh install. When I tried this, It didnt give me any drive options, other then my external drives. For the heck of it, I tried to install to one of the external drives, went through its process, and when it reboot, it just loaded osx normally from my internal SSD. Im at a loss, as to why it wont work for me. Anyone have any thoughts about this?