After upgrading xcode4.1/ios4 to xcode4.2/ios5 I am experiencing crashes while the App is loading and before it even enters main()
.
Xcode 4.2 still has some rough edges from my usage. A complete removal and re-install fixed an issue I had (it was stuck on "Attaching" and none of the solutions on the "official" SO thread helped). Might be a bit extreme though.
Select the top-level project in the File Navigator and go to the Build Phases tab. Expand "Link Binary with Frameworks" section—are there any frameworks that aren't Apple-provided? Are they Optional or Required? And does any of your code required any additional frameworks?
To help more could you post all the log messages that are currently being obscured by the call stack popup?