The Darwin source code is available at http://www.opensource.apple.com/darwinsource/. However, downloading it is painful. There are a million little tarballs. There needs to be a better way of downloading the source. We should be able to download it all at once, maybe in one big disk image. 27-May-2009 : Engineering has requested the following information in order to further investigate this issue: 1. install darwinbuild via MacPorts or http://darwinbuild.macosforge.org/ 2. mkdir 9G55 && cd 9G55 3. sudo -s 4. darwinbuild -init 9G55 5. for X in `darwinxref version '*' | cut -d '-' -f 1`; do darwinbuild -fetch $X; done 6. mkdir AllSource 7. for X in Sources/*; do tar zxvf $X -C AllSource/; done Please update us with your results. 28-May-2009 Jeff Johnson: This issue has been verified as resolved and can be closed. Thanks! That works. Note that steps 6 and 7 should probably not be done as root, otherwise the source files will not be writable except by root, which is not ideal.