Hi, I've installed the cctbx package from the selfextracting file found in http://cci.lbl.gov/cctbx_build/ but I run into problems when importing cctbx in my python script: import iotbx.pdb File "/Users/magnus/Downloads/cctbx_sources/iotbx/pdb/__init__.py", line 2, in <module> from cctbx.array_family import flex File "/Users/magnus/Downloads/cctbx_sources/cctbx/array_family/flex.py", line 2, in <module> import scitbx.array_family.flex File "/Users/magnus/Downloads/cctbx_sources/scitbx/array_family/flex.py", line 2, in <module> import boost.optional # import dependency ImportError: No module named boost.optional It is flex.py that wants to import boost.optional and does not find it. However, I find these three files: optional.hpp optional_fwd.hpp optional_io.hpp in the following directory: /Users/magnus/Downloads/cctbx_sources/boost/boost/optional which suggests that it's present. What am I missing here? I'm using Mac OS X Version 10.9.3 and Python2.7. Cheers, Magnus