I just to upgraded OS X to maverics and to xcode 5.
Now I can't launch my app which was running just fine on iOS 6.1 simulator, now I only see black screen both on simulator (I tried 6.0, 6.1 and 7.1), and also on a real device.
I put breakpoint into main function in my main.m and it is not called.
How can I debug this further? I googled this, and did all suggestions like resetting simulator, reinstalling xcode, deleting /Library/Application Support/iPhone Simulator/* nothing helped.
Also, if I start new app from scratch in xcode it runs fine.
SOLVED: Actually the problem was that debugger was not attaching to the process, so I did not see what was happening (also console showed nothing), and app did stop launching due to some exception in my code.
Double click on the simulator icon on the dock (multiple times if required), sometimes it doesn't attach well to the process of the simulator.
If it still doesn't work, go back to home screen (cmd + shift + h), and touch your app again: XCode should then attach!