Xcode4 Linking Problem. File was built for archive which is not the architecture being linked (arm6)

Question

Recently, I switched to Xcode4 and when I compile my project I got following error.

ld: warning: ignoring file /Users/myname/Library/Developer/Xcode/DerivedD         


        

Answer 1

None of these answers worked for me. (Similar warning message, different static library project). For me it was having configured XCode to honor the build directories of the targets and then having targets build in a local build/ directory that caused the problem. Configuring XCOde to use "Derived data" folder fixed it.