Failed to launch simulated application: Unknown error

Question

• OS X 10.5.7 (genuine Mac)
• Xcode 3.1.3
• iPhone SDK 3.0

When I try to execute my iPhone application in simulator, I get the dreaded error

Answer 1

I use the Rename Project option to change my project's name and everything worked after that. I think we're all dancing around any number of methods of "fixing" whatever internal files XCode uses to track what it's doing. Pretty frustrating bug.