Hi, On VS2010, the following code does not compile if I restore the commented out #include: *// #include <boost/property_tree/json_parser.hpp>* struct X { enum Labels { ERROR, ONE, TWO, THREE }; // problem => ^^^^^ }; void f() { X::Labels r = X::ERROR; // problem => ^^^^^ } The VS2010 errors are: t.cpp(5): error C2059: syntax error : 'constant' t.cpp(5): error C2143: syntax error : missing ';' before '}' t.cpp(5): error C2238: unexpected token(s) preceding ';' t.cpp(7): error C2059: syntax error : '}' t.cpp(7): error C2143: syntax error : missing ';' before '}' t.cpp(7): error C2059: syntax error : '}' t.cpp(11): error C2589: 'constant' : illegal token on right side of '::' t.cpp(11): error C2059: syntax error : '::' It seems that somewhere inside the #include hierarchy the symbol ERROR is #defined to cause this code to fail. Renaming ERROR to something else avoids this problem. I think I tracked it into ' boost/spirit/home/classic/iterator/impl/file_iterator.ipp' but I'm not sure where exactly it is coming from. Adi