Xcode: Internal error occurred while creating dependency graph

Question

I just started getting this error today, seemingly out of nowhere. Any one see this before and know what causes it.

Internal error occurred while creating dependency graph: *** -[NSCFArray initWithObjects:count:]: attempt to insert nil object at objects[10]

This happens when I try to build with "iPhone Device 3.x" selected. However, if I select "iPhone Simulator 3.x", everything is fine.

I am using Xcode 3.2.1.

Answer 1

I found the solution to my problem and it was quite simple.

1. Quit Xcode
2. Reopen Xcode
3. Open your project
4. Clean All Targets

Now everything works fine although I wish I knew how I got into that state.