I have installed boost on both Windows and AIX and get the same problem when I try to compile the simple_ls.cpp program that boost provides. In AIX the boost hpp files get installed in /usr/local/include/boost-1_32/boost/... I created /usr/local/include/boost/... with this command: ln -s /usr/local/include/boost-1_32/boost /usr/local/include/boost In Windows the boost hpp files get installed C:\boost-1_32\boost\... In AIX when I try to compile simple_ls.cpp I get the following: "/usr/local/include/boost/filesystem/operations.hpp", line 18.10: 1540-0836 (S) The #include file is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 19.10: 1540-0836 (S) The #include file is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 21.10: 1540-0836 (S) The #include file is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 22.10: 1540-0836 (S) The #include file is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 27.10: 1540-0836 (S) The #include file is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 149.10: 1540-0836 (S) The #include file is not found. my simple_ls.cpp currently has the following include statements: #include "/usr/local/include/boost/filesystem/operations.hpp" #include "/usr/local/include/boost/filesystem/path.hpp" #include <iostream> simple_ls.cpp came with the following include statements which generate similar errors to those above: #include "boost/filesystem/operations.hpp" #include "boost/filesystem/path.hpp" #include <iostream> MS Visual C++ 6 generates the following similar error when attempting to compile simple_ls.cpp c:\boost\include\boost-1_32\boost\filesystem\operations.hpp(18) : fatal error C1083: Cannot open include file: 'boost/filesystem/path.hpp': No such file or directory Thanks for any tips.