Hello all, I have made an app using an external C library: libqrencode, installed using Macports. I am using XCode 3.2.5 on a MacBook Pro Mid 2009. The debug version builds just fine. However, the release build gives me the warning: "in /opt/local/lib/libqrencode.3.dylib, file was built for unsupported file format which is not the architecture being linked (i386)" with undefined symbols errors. I have tried several configuration: For Mac OS X 10.6 SDK: Debug | x86_64 : works fine Debug | i386 : error Release | x86_64 : error Release | i386 : error For Mac OS X 10.5 SDK: Nothing compiles. I have checked the header, user, library, framework search path for each configuration. Any suggestions ?