Xcode 4: Build Failed, No Issues

Question

The app works fine in the simulator, builds and runs.

When I attach my device (iPhone 3GS running iOS 4.3) and target the iPhone, the result is \"Build failed\" with

Answer 1

seems like there are many possible causes of this problem. Mine turned out to be that

My target was set to use a non-existent provisioning profile.

I set my project to use a new profile, and I deleted the old one. Didn't realize that the target had its own provisioning profile setting, which was still set to the old (now deleted) profile.