Had the same problem. Last played a month or so ago and about 200+ hours before that. Went to Uplay's home page, clicked on FC4 and hit play. Got the loading screen with the rotating balls in the lower right corner and nothing after that...........after trying a bunch of things but thankfully not a reinstall...........FOUND A SOLUTION.............went to the programming files on my computer........."C:\Program Files (x86)\Ubisoft\FarCry 4\bin\FarCry4.exe"................and started the program from there. Worked like a charm. Started right up like it always did. Put a short cut on my desktop. Might be wrong but I think the problem has something to do with UPlay updating their site over the last month or so. Would bet that some of the hot keys are sending the wrong signal for some people. I now have 2 short cuts for FC4. One is what I have shown above and the other has a WEB Document (uplay://launch/420) in the properties instead of a shortcut tab. Think this the problem somehow.