I am currently experiencing this as well. I was working on my campaign for hours into the wee hours of the night (morning?) when I accidentally closed the window. When I went to go back in, it just sits on the loading screen. I left it up all night, just in case it was due to large amounts of campaign info, but no go. I rebooted my machine as I left for work, and will try again when I get home. I will try the shift-Reload as well... I have already cleared the cache, and that did not work. I hope that I did not lose all that work!!!