Kevin, 1. To build the libsecurity_keychain, I ran # darwinbuild libsecurity_keychain I got an error: CoreFoundation/CFNotificationCenter.h: No such file or directory. Try to solve this problem, I ran # darwinbuild CF I still got errors. Do I need to set up the header file environment first or I need to run Some patch file? 2. To build the IOUSBMassStorageClass, I ran # darwinbuild IOUSBMassStorageClass I got an error: IOKit/scsi-commands/IOSCSIProtocolServices.h: No such file or directory. To run darwinbuild on a project, is there a general rule to follow? I mean If a build failed due to the build order, I can easily to figure out what I should do. Thanks a lot, Ben