Xcode Build Issue

I've been having some trouble with Xcode. Every time I launch my application, it opens in the simulator and then immediately closes. Xcode says it build successfully and there are no errors.

This happened when I added a timer to my application, however I have now reverted to the previous save where there is no mention of this timer and 开发者_JS百科I *know it was working then, but it still happens the same way.

Does anyone else get this?

search on SO for the debug flag to turn on in XCode so that you get a stack trace on program exit (I can't find it and my mac machine is not available)

It's NSZombieEnabled, see here