diff --git a/CHANGELOG.md b/CHANGELOG.md
index 67a2632b93..ebda3d4f8e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -185,6 +185,7 @@
     Bug #5223: Bow replacement during attack animation removes attached arrow
     Bug #5226: Reputation should be capped
     Bug #5229: Crash if mesh controller node has no data node
+    Bug #5239: OpenMW-CS does not support non-ASCII characters in path names
     Feature #1774: Handle AvoidNode
     Feature #2229: Improve pathfinding AI
     Feature #3025: Analogue gamepad movement controls
diff --git a/apps/essimporter/importer.cpp b/apps/essimporter/importer.cpp
index a54c133340..36512579ce 100644
--- a/apps/essimporter/importer.cpp
+++ b/apps/essimporter/importer.cpp
@@ -2,6 +2,7 @@
 
 #include <iomanip>
 
+#include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
 
 #include <osgDB/ReadFile>
@@ -349,7 +350,7 @@ namespace ESSImport
 
         writer.setFormat (ESM::SavedGame::sCurrentFormat);
 
-        std::ofstream stream(mOutFile.c_str(), std::ios::binary);
+        boost::filesystem::ofstream stream(boost::filesystem::path(mOutFile), std::ios::out | std::ios::binary);
         // all unused
         writer.setVersion(0);
         writer.setType(0);
diff --git a/apps/opencs/model/doc/document.cpp b/apps/opencs/model/doc/document.cpp
index 03693ddfe2..3a20555d1e 100644
--- a/apps/opencs/model/doc/document.cpp
+++ b/apps/opencs/model/doc/document.cpp
@@ -1,7 +1,6 @@
 #include "document.hpp"
 
 #include <cassert>
-#include <fstream>
 
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
@@ -289,19 +288,22 @@ CSMDoc::Document::Document (const Files::ConfigurationManager& configuration,
 
     if (mNew || !boost::filesystem::exists (mProjectPath))
     {
-        boost::filesystem::path customFiltersPath (configuration.getUserDataPath());
-        customFiltersPath /= "defaultfilters";
-
-        std::ofstream destination (mProjectPath.string().c_str(), std::ios::binary);
-
-        if (boost::filesystem::exists (customFiltersPath))
-        {
-            destination << std::ifstream(customFiltersPath.string().c_str(), std::ios::binary).rdbuf();
-        }
-        else
-        {
-            destination << std::ifstream(std::string(mResDir.string() + "/defaultfilters").c_str(), std::ios::binary).rdbuf();
-        }
+        boost::filesystem::path filtersPath (configuration.getUserDataPath() / "defaultfilters");
+
+        boost::filesystem::ofstream destination(mProjectPath, std::ios::out | std::ios::binary);
+        if (!destination.is_open())
+            throw std::runtime_error("Can not create project file: " + mProjectPath.string());
+        destination.exceptions(std::ios::failbit | std::ios::badbit);
+
+        if (!boost::filesystem::exists (filtersPath))
+            filtersPath = mResDir / "defaultfilters";
+
+        boost::filesystem::ifstream source(filtersPath, std::ios::in | std::ios::binary);
+        if (!source.is_open())
+            throw std::runtime_error("Can not read filters file: " + filtersPath.string());
+        source.exceptions(std::ios::failbit | std::ios::badbit);
+
+        destination << source.rdbuf();
     }
 
     if (mNew)
diff --git a/components/detournavigator/debug.cpp b/components/detournavigator/debug.cpp
index 0ddf002d90..c3d67b1848 100644
--- a/components/detournavigator/debug.cpp
+++ b/components/detournavigator/debug.cpp
@@ -4,14 +4,15 @@
 
 #include <DetourNavMesh.h>
 
-#include <fstream>
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
 
 namespace DetourNavigator
 {
     void writeToFile(const RecastMesh& recastMesh, const std::string& pathPrefix, const std::string& revision)
     {
         const auto path = pathPrefix + "recastmesh" + revision + ".obj";
-        std::ofstream file(path);
+        boost::filesystem::ofstream file(boost::filesystem::path(path), std::ios::out);
         if (!file.is_open())
             throw NavigatorException("Open file failed: " + path);
         file.exceptions(std::ios::failbit | std::ios::badbit);
@@ -64,7 +65,7 @@ namespace DetourNavigator
         };
 
         const auto path = pathPrefix + "all_tiles_navmesh" + revision + ".bin";
-        std::ofstream file(path, std::ios::binary);
+        boost::filesystem::ofstream file(boost::filesystem::path(path), std::ios::out | std::ios::binary);
         if (!file.is_open())
             throw NavigatorException("Open file failed: " + path);
         file.exceptions(std::ios::failbit | std::ios::badbit);