Why doesn't Xcode 4 create any products?

Xcode 4 places its build products and other intermediaries/temporary files/indexes in a derived data directory now instead of a "build" directory that is mixed in with your product files. It does this to deal with the new workspaces and also so that you can have clean builds of different projects in different workspaces without contaminating each other.

If your original template was old, your built product is probably relative to your source directory instead of relative to your built products directory, which is why it's showing up red. By default, your derived data directory will be under ~/Library/Developer/Xcode/DerivedData. To see where your current workspace/project is placing these files, you can File->Workspace Settings... and take a look at the Build Location.

I was having this problem. not only the product .app was red, also simulator wasn't loaded the binary, it was stuck in attaching 'my app'. i solved it by going to file->project settings. in the tab 'build' changed derived data location to 'project-relative', and in advanced changed build location to 'locations specified by targets'. with the default options it wasn't possible to run the app, i'm not sure why.

To resolve the issue in XCode 4.x go through following steps :-

Open your project in XCode.

Select .xcodeproj file in XCode project Navigator.

Select the target under the PROJECT Heading. (i.e. the top most target, this target specify your project level build settings)

Now navigate to Build Settings.

Now search for option "Per-Configuration Build Products Path" and update it's value to $(SYMROOT) .