Xcode, Duplicate symbol _main

Question

I have duplicate symbol _main.

The problem is it says \"Duplicate symbol _main in /Users/.../i386/main-B9843B6026D6EFA4.o and /Users/.../i386/main-B9843B6026D6EFA4.o

Answer 1

I had the same problem opening a project, that was created with Xcode 4.0.2, with Xcode 4.1. I simply solved by clicking on "Modernize Project" (Editor/Modernize Project). This procedure automatically removed all duplicates.