diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 30018c53da..025762f0e8 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -83,6 +83,7 @@
 #include "ardour/slave.h"
 #include "ardour/system_exec.h"
 #include "ardour/directory_names.h"
+#include "ardour/filename_extensions.h"
 #include "dbg_msg.h"
 
 #ifdef WINDOWS_VST_SUPPORT
@@ -2670,6 +2671,105 @@ ARDOUR_UI::idle_load (const std::string& path)
 	}
 }
 
+namespace
+{
+    void run_message_dialog(std::string message)
+    {
+        MessageDialog msg (message.c_str(), false, Gtk::MESSAGE_WARNING, Gtk::BUTTONS_OK, true);
+        msg.set_keep_above(true);
+        msg.set_position (Gtk::WIN_POS_MOUSE);
+        msg.run();
+    }
+    
+    void init_suffices(std::vector<std::string>& suffices)
+    {
+        suffices.push_back(template_suffix);
+        suffices.push_back(statefile_suffix);
+        suffices.push_back(pending_suffix);
+        suffices.push_back(peakfile_suffix);
+        suffices.push_back(backup_suffix);
+        suffices.push_back(temp_suffix);
+        suffices.push_back(history_suffix);
+        suffices.push_back(export_preset_suffix);
+        suffices.push_back(export_format_suffix);
+        suffices.push_back("instant.xml");
+    }
+    
+    void init_directories(std::vector<std::string>& directories)
+    {
+        directories.push_back(string(peak_dir_name));
+        directories.push_back(string(dead_dir_name));
+        directories.push_back(string(export_dir_name));
+        directories.push_back(string(analysis_dir_name)); 
+        directories.push_back(string(plugins_dir_name));
+        directories.push_back(string(externals_dir_name));
+        directories.push_back(string(".DS_Store"));
+    } 
+    
+    bool is_tracks_file(std::string full_file_name)
+    {
+        std::vector<std::string> suffices;
+        init_suffices(suffices);
+        
+        for(int i = 0; i < suffices.size(); i++)
+        {
+            int pos = full_file_name.rfind(suffices[i]);
+            // if suffix locates at the end of the full_file_name
+            if( pos == full_file_name.size() - suffices[i].size() )
+                return true;
+        }
+        
+        return false;
+    }
+    
+    /*@directory_name for example is "analysis", "example", etc. It is not a full path. */
+    bool is_tracks_directory(std::string directory_name)
+    {
+        std::vector<std::string> directories;
+        init_directories(directories);
+        
+        return std::find(directories.begin(), directories.end(), directory_name) != directories.end();
+    }
+
+}
+
+
+// return true if session was successfully deleted
+bool
+ARDOUR_UI::delete_session_files(std::string session_path)
+{
+    GDir *dir;
+    GError *error;
+    const gchar *file_name;
+    
+    dir = g_dir_open(session_path.c_str(), 0, &error);
+    
+    bool result = true;
+    
+    while ((file_name = g_dir_read_name(dir)))
+    {
+        string object_name = string(file_name);
+        string full_object_name = Glib::build_filename( session_path, string(file_name) );
+        
+        bool is_directory = Glib::file_test(full_object_name, Glib::FileTest (G_FILE_TEST_IS_DIR));
+        
+        if( is_directory && is_tracks_directory(file_name) )
+        {
+            result = result && delete_session_files(full_object_name);
+            g_remove(full_object_name.c_str());
+        } else {
+            if( !is_directory && is_tracks_file(full_object_name) )
+                if( g_remove(full_object_name.c_str()) == -1 )
+                {
+                    run_message_dialog("Can't remove file: " + full_object_name);
+                    result = false;
+                }
+        }
+    } 
+    
+    return result;
+}
+
 /** @param quit_on_cancel true if exit() should be called if the user clicks `cancel' in the new session dialog */
 int
 ARDOUR_UI::get_session_parameters (bool quit_on_cancel, bool should_be_new, string load_template)
@@ -2677,12 +2777,13 @@ ARDOUR_UI::get_session_parameters (bool quit_on_cancel, bool should_be_new, stri
 	string session_name;
 	string session_path;
 	string template_name;
+    string full_session_name;
 	int ret = -1;
 	bool likely_new = false;
 	bool cancel_not_quit;
 
 	/* deal with any existing DIRTY session now, rather than later. don't
-	 * treat a non-dirty session this way, so that it stays visible 
+	 * treat a non-dirty session this way, so that it stays visible
 	 * as we bring up the new session dialog.
 	 */
 
@@ -2769,10 +2870,10 @@ ARDOUR_UI::get_session_parameters (bool quit_on_cancel, bool should_be_new, stri
 		/* if we run the startup dialog again, offer more than just "new session" */
 		
 		should_be_new = false;
-		
-		session_name = session_dialog.session_name (likely_new);
+        
+		full_session_name = session_name = session_dialog.session_name (likely_new);
 		session_path = session_dialog.session_folder ();
-
+        
 		if (nsm) {
 		        likely_new = true;
 		}
@@ -2786,6 +2887,7 @@ ARDOUR_UI::get_session_parameters (bool quit_on_cancel, bool should_be_new, stri
 		/* this shouldn't happen, but we catch it just in case it does */
 		
 		if (session_name.empty()) {
+            run_message_dialog("Session name is invalid");
 			continue;
 		}
 		
@@ -2825,108 +2927,36 @@ ARDOUR_UI::get_session_parameters (bool quit_on_cancel, bool should_be_new, stri
 			}
 		}
 	
-		if (Glib::file_test (session_path, Glib::FileTest (G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR))) {
+		if ( Glib::file_test (session_path, Glib::FileTest (G_FILE_TEST_EXISTS)) ) {
 
 
 			if (likely_new && !nsm) {
-
-				std::string existing = Glib::build_filename (session_path, session_name);
                 
                 bool do_not_create_session = false;
-
-                GDir *dir;
-                GError *error;
-                const gchar *file_name;
                 
-                dir = g_dir_open(session_path.c_str(), 0, &error);
+                // Replace session only if file with extension '.ardour' was chosen
+                string suffix = string(statefile_suffix);
                 
-                while ((file_name = g_dir_read_name(dir)))
+                // if existed folder was choosen
+                if( Glib::file_test (full_session_name, Glib::FileTest (G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR)) )
                 {
-                    string ff = string(file_name);
-                    
-                    string full_file_name = g_build_filename(session_path.c_str(), file_name);
-                    
-                    string str_file_name = string(file_name);
-                    string interchange_debug = string(ARDOUR::interchange_dir_name);
-                    
-                    if( (g_file_test (full_file_name.c_str(), GFileTest (G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR))) &&
-                        (str_file_name == interchange_debug) )
-                    {
-                        cout<<endl<<full_file_name<<" WAS NOT deleted \n\n"<<flush;
-                        continue;
-                    }
-
-                    if( g_file_test (full_file_name.c_str(), GFileTest (G_FILE_TEST_EXISTS)) &&
-                        string(file_name) != string(ARDOUR::interchange_dir_name) )
-                    {
-                        
-                        try {
-                            if( g_remove(full_file_name.c_str() ) >=0 )
-                                cout<<full_file_name<<" file was deleted \n"<<flush;
-                            else
-                            {
-                                cout<<full_file_name<<" file was not deleted (ELSE) \n"<<flush;
-                                
-                                string message = "Can not replace session. File: file " + full_file_name + " can not be deleted";
-                                MessageDialog msg (message.c_str(),
-                                                   false,
-                                                   Gtk::MESSAGE_WARNING,
-                                                   Gtk::BUTTONS_OK,
-                                                   true);
-                                
-                                msg.set_position (Gtk::WIN_POS_MOUSE);
-                                msg.run();
-                                
-                                do_not_create_session = true;
-                                break;                           
-                            }
-    
-                        } catch (...) {
-                            cout<<full_file_name<<" file was not deleted (CATCH) \n"<<flush;
-                            
-                            string message = "Can not replace session. File: file " + full_file_name + " can not be deleted";
-                            MessageDialog msg (message.c_str(),
-                                               false,
-                                               Gtk::MESSAGE_WARNING,
-                                               Gtk::BUTTONS_OK,
-                                               true);
-                            
-                            msg.set_position (Gtk::WIN_POS_MOUSE);
-                            msg.run();
-                            
-                            do_not_create_session = true;
-                            break;
-                        }
-                        
-                        /*
-                        // file is a directory
-                        if( (Glib::file_test (full_file_name, Glib::FileTest (G_FILE_TEST_IS_DIR))) )
-                        {
-                            try {
-                                if( g_rmdir(full_file_name.c_str())>=0 )
-                                    cout<<full_file_name<<" directory was deleted \n"<<flush;
-                                else
-                                    cout<<full_file_name<<" directory was not deleted \n"<<flush;
-                            } catch (...) {
-                                cerr<<"ERROR :: Can not delete directroy: "<<file_name<<endl<<flush;
-                            }
-                        } else {
-                            // file is not a directory
-                            try {
-                                if(unlink(full_file_name.c_str())>=0)
-                                    cout<<full_file_name<<" file was deleted"<<endl<<flush;
-                                else
-                                    cout<<full_file_name<<" file was not deleted"<<endl<<flush;
-                            } catch (...) {
-                                cerr<<"ERROR :: Can not delete file: "<<file_name<<endl<<flush;    
-                            }
-                            
-                        }
-                         */
-                    }
+                    run_message_dialog("Can not replace session. Folder " + session_path + " allready exists. If you need to replace session please choose file " + full_session_name + suffix);
+                    continue;
                 }
+                    
+                int pos = full_session_name.rfind(suffix);
                 
-                if( do_not_create_session )
+                // if not *.ardour file was choosen
+                if( !(pos == full_session_name.size() - suffix.size()) )
+                {
+                    run_message_dialog("Invalid file name. In order to replace session select *" + suffix + " projectfile");
+                    
+                    continue;
+                }
+                    
+                
+                // .ardour file was choosen. Replace session: delete existing session
+                if( !delete_session_files(session_path) )
                     continue;
                 
                 _session_is_new = true;
diff --git a/gtk2_ardour/ardour_ui.h b/gtk2_ardour/ardour_ui.h
index 0fba0607d4..2f66dbc560 100644
--- a/gtk2_ardour/ardour_ui.h
+++ b/gtk2_ardour/ardour_ui.h
@@ -340,6 +340,8 @@ class ARDOUR_UI : public Gtkmm2ext::UI, public ARDOUR::SessionHandlePtr
 	void setup_transport ();
 	void setup_transport_trx ();
 	void setup_clock ();
+    
+    bool delete_session_files(std::string session_path);
 
 	static ARDOUR_UI *theArdourUI;
 
diff --git a/libs/ardour/ardour/directory_names.h b/libs/ardour/ardour/directory_names.h
index 17532e2a3a..c314f30c89 100644
--- a/libs/ardour/ardour/directory_names.h
+++ b/libs/ardour/ardour/directory_names.h
@@ -43,6 +43,10 @@ namespace ARDOUR {
 	LIBARDOUR_API extern const char* const user_config_dir_name;
 	LIBARDOUR_API extern const char* const panner_dir_name;
 	LIBARDOUR_API extern const char* const backend_dir_name;
+    LIBARDOUR_API extern const char* const automation_dir_name;
+    LIBARDOUR_API extern const char* const analysis_dir_name;
+    LIBARDOUR_API extern const char* const plugins_dir_name;
+    LIBARDOUR_API extern const char* const externals_dir_name;
 
 };
 
diff --git a/libs/ardour/directory_names.cc b/libs/ardour/directory_names.cc
index c368f8eaaf..c763897bc2 100644
--- a/libs/ardour/directory_names.cc
+++ b/libs/ardour/directory_names.cc
@@ -39,6 +39,10 @@ const char* const surfaces_dir_name = X_("surfaces");
 const char* const ladspa_dir_name = X_("ladspa");
 const char* const panner_dir_name = X_("panners");
 const char* const backend_dir_name = X_("backends");
+const char* const automation_dir_name = X_("automation");
+const char* const analysis_dir_name = X_("analysis");
+const char* const plugins_dir_name = X_("plugins");
+const char* const externals_dir_name = X_("externals");
 
 char config_dir_name[] = X_(PROGRAM_NAME "3");
 #if defined (__APPLE__) || defined (PLATFORM_WINDOWS)
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 527ee2b32d..4312260dd4 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -127,19 +127,6 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
-namespace
-{
-    string
-    get_session_projectfile_name(string session_path)
-    {
-        string s0 = session_path;
-        string s1 = Glib::path_get_dirname (s0);
-        s0.erase(0, s1.size());
-        
-        return session_path + s0 + ".ardour";
-    }
-}
-
 void
 Session::pre_engine_init (string fullpath)
 {
@@ -160,7 +147,10 @@ Session::pre_engine_init (string fullpath)
     
 	/* is it new ? */
 
-	_is_new = !Glib::file_test ( get_session_projectfile_name(fullpath), Glib::FileTest (G_FILE_TEST_EXISTS));
+    string full_session_name = Glib::build_filename( fullpath, _name );
+    full_session_name += statefile_suffix;
+    
+	_is_new = !Glib::file_test ( full_session_name, Glib::FileTest (G_FILE_TEST_EXISTS));
 
 	/* finish initialization that can't be done in a normal C++ constructor
 	   definition.
@@ -421,15 +411,17 @@ Session::ensure_subdirs ()
 
 	dir = session_directory().peak_path();
 
-	if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-		error << string_compose(_("Session: cannot create session peakfile folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-		return -1;
-	}
-
+    // if directory allready exists do not create it again
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session peakfile folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
+    }
+    
 	dir = session_directory().sound_path();
 
-    // if directory 'interchange' allready exists do not create it again
-    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR))) {
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
         if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
             error << string_compose(_("Session: cannot create session sounds dir \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
             return -1;
@@ -438,45 +430,57 @@ Session::ensure_subdirs ()
 
 	dir = session_directory().midi_path();
    
-    if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-        error << string_compose(_("Session: cannot create session midi dir \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-        return -1;
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session midi dir \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
     }
-
+    
 	dir = session_directory().dead_path();
 
-	if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-		error << string_compose(_("Session: cannot create session dead sounds folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-		return -1;
-	}
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session dead sounds folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
+    }
 
 	dir = session_directory().export_path();
 
-	if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-		error << string_compose(_("Session: cannot create session export folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-		return -1;
-	}
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session export folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
+    }
 
 	dir = analysis_dir ();
 
-	if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-		error << string_compose(_("Session: cannot create session analysis folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-		return -1;
-	}
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session analysis folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
+    }
 
 	dir = plugins_dir ();
 
-	if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-		error << string_compose(_("Session: cannot create session plugins folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-		return -1;
-	}
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session plugins folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
+    }
 
 	dir = externals_dir ();
 
-	if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
-		error << string_compose(_("Session: cannot create session externals folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
-		return -1;
-	}
+    if ( !Glib::file_test (dir.c_str(), Glib::FileTest (G_FILE_TEST_EXISTS))) {
+        if (g_mkdir_with_parents (dir.c_str(), 0755) < 0) {
+            error << string_compose(_("Session: cannot create session externals folder \"%1\" (%2)"), dir, strerror (errno)) << endmsg;
+            return -1;
+        }
+    }
 
 	return 0;
 }
@@ -2207,25 +2211,25 @@ Session::get_best_session_directory_for_new_source ()
 string
 Session::automation_dir () const
 {
-	return Glib::build_filename (_path, "automation");
+	return Glib::build_filename (_path, automation_dir_name);
 }
 
 string
 Session::analysis_dir () const
 {
-	return Glib::build_filename (_path, "analysis");
+	return Glib::build_filename (_path, analysis_dir_name);
 }
 
 string
 Session::plugins_dir () const
 {
-	return Glib::build_filename (_path, "plugins");
+	return Glib::build_filename (_path, plugins_dir_name);
 }
 
 string
 Session::externals_dir () const
 {
-	return Glib::build_filename (_path, "externals");
+	return Glib::build_filename (_path, externals_dir_name);
 }
 
 int