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

Make sure the build variants on your projects are set to "normal".

If you are building a project which includes other projects, take a look inside the DerivedData folder for the main project. Examine the archive files with the "lipo -info yourarchive.a". Also, examine the timestamps on these archives. You may find that these libraries are not getting rebuilt or you are trying to link against an old version of the archive which is the wrong architecture.

In my case, I shutdown Xcode and deleted the DerivedData folder for my main project. This forced a full rebuild when I reopened the main project in Xcode 4. The full rebuild caused the i386 archives to be created (or the correct version to be found) & the simulator version to link correctly.