Tldr Boost dylibs are not linking to my xcode project properly. I have no idea why. I realise this is something of a problem on the internet, but after 45 minutes of googling I haven't found a solution to my problem. Okay - so I'm trying to link in the boost filesystem library to my Xcode 4.1 project. So far I've unpacked and installed the boost libraries, and linked to them through my header and search paths in xcodes build settings. So, if I try to compile the program at this point I get linker errors, cannot find boost etc. Linking to the static boost libraries (for example boost::rand) works fine. So it must be the dynamic libraries that are the problem. If I drag and drop the dylibs from the boost install directory into the build phases box the project compiles fine, but I get symbol errors when I run the program (which I have gleaned means that there are still linker errors). Any help anyone can provide would be really appreciated.