diff --git a/include/nana/filesystem/filesystem_ext.hpp b/include/nana/filesystem/filesystem_ext.hpp
index 7e33ae9e..289bab0a 100644
--- a/include/nana/filesystem/filesystem_ext.hpp
+++ b/include/nana/filesystem/filesystem_ext.hpp
@@ -15,6 +15,8 @@
 #ifndef NANA_FILESYSTEM_EXT_HPP
 #define NANA_FILESYSTEM_EXT_HPP
 
+#include <nana/filesystem/filesystem_selector.hpp>
+
 namespace nana {namespace experimental {namespace filesystem {namespace ext {
 #if defined(NANA_WINDOWS)
     constexpr auto def_root = "C:";
diff --git a/include/nana/filesystem/filesystem_selector.hpp b/include/nana/filesystem/filesystem_selector.hpp
index b168ce30..af4cf298 100644
--- a/include/nana/filesystem/filesystem_selector.hpp
+++ b/include/nana/filesystem/filesystem_selector.hpp
@@ -28,7 +28,7 @@
 
 #include <nana/config.hpp>
 
-#if defined(NANA_BOOST_FILESYSTEM_AVAILABLE) && ( defined(NANA_BOOST_FILESYSTEM_FORCE) || (defined(STD_FILESYSTEM_NOT_SUPPORTED) && defined(NANA_BOOST_FILESYSTEM_PREFERRED) ) )
+#if (!defined(NANA_FILESYSTEM_FORCE) && defined(NANA_BOOST_FILESYSTEM_AVAILABLE) && ( defined(NANA_BOOST_FILESYSTEM_FORCE) || (defined(STD_FILESYSTEM_NOT_SUPPORTED) && defined(NANA_BOOST_FILESYSTEM_PREFERRED) ) ))
 
 #   include <boost/filesystem.hpp>
 
@@ -48,7 +48,7 @@ namespace std {
 } // std
 
 
-#elif defined(STD_FILESYSTEM_NOT_SUPPORTED)
+#elif  (defined(NANA_FILESYSTEM_FORCE) || defined(STD_FILESYSTEM_NOT_SUPPORTED))
 
 #   include <nana/filesystem/filesystem.hpp>