diff --git a/MUtilities_VS2017.vcxproj b/MUtilities_VS2017.vcxproj
index b919019..b12d076 100644
--- a/MUtilities_VS2017.vcxproj
+++ b/MUtilities_VS2017.vcxproj
@@ -64,6 +64,7 @@
     <ClInclude Include="src\3rd_party\keccak\include\keccak_impl.h" />
     <ClInclude Include="src\3rd_party\strnatcmp\include\strnatcmp.h" />
     <ClInclude Include="src\DirLocker.h" />
+    <ClInclude Include="src\Internal.h" />
     <ClInclude Include="src\Mirrors.h" />
     <ClInclude Include="src\Utils_Win32.h" />
     <CustomBuild Include="include\Mutils\UpdateChecker.h">
diff --git a/MUtilities_VS2017.vcxproj.filters b/MUtilities_VS2017.vcxproj.filters
index 685cfb1..f710dc2 100644
--- a/MUtilities_VS2017.vcxproj.filters
+++ b/MUtilities_VS2017.vcxproj.filters
@@ -182,6 +182,9 @@
     <ClInclude Include="src\Mirrors.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="src\Internal.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <CustomBuild Include="include\Mutils\UpdateChecker.h">
diff --git a/src/Global.cpp b/src/Global.cpp
index 6c8c7ec..7b079f3 100644
--- a/src/Global.cpp
+++ b/src/Global.cpp
@@ -27,6 +27,7 @@
 #include <MUtils/Global.h>
 #include <MUtils/OSSupport.h>
 #include <MUtils/Version.h>
+#include "Internal.h"
 
 //Internal
 #include "DirLocker.h"
@@ -53,6 +54,9 @@
 #include <vld.h>
 #endif
 
+//Global
+const QString MUtils::Internal::g_empty;
+
 ///////////////////////////////////////////////////////////////////////////////
 // Random Support
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/src/Internal.h b/src/Internal.h
new file mode 100644
index 0000000..cd4e202
--- /dev/null
+++ b/src/Internal.h
@@ -0,0 +1,30 @@
+///////////////////////////////////////////////////////////////////////////////
+// MuldeR's Utilities for Qt
+// Copyright (C) 2004-2018 LoRd_MuldeR <MuldeR2@GMX.de>
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+//
+// http://www.gnu.org/licenses/lgpl-2.1.txt
+//////////////////////////////////////////////////////////////////////////////////
+
+#include <QString>
+
+namespace MUtils
+{
+	namespace Internal
+	{
+		extern const QString g_empty;
+	}
+}
diff --git a/src/OSSupport_Win32.cpp b/src/OSSupport_Win32.cpp
index 6c43890..48fe8f1 100644
--- a/src/OSSupport_Win32.cpp
+++ b/src/OSSupport_Win32.cpp
@@ -40,6 +40,7 @@
 #include <MUtils/Global.h>
 #include <MUtils/OSSupport.h>
 #include <MUtils/GUI.h>
+#include "Internal.h"
 #include "CriticalSection_Win32.h"
 #include "Utils_Win32.h"
 
@@ -681,13 +682,12 @@ const bool &MUtils::OS::running_on_wine(void)
 // KNWON FOLDERS
 ///////////////////////////////////////////////////////////////////////////////
 
-typedef QMap<size_t, QString> KFMap;
+static QReadWriteLock                         g_known_folders_lock;
+static QScopedPointer<QHash<size_t, QString>> g_known_folders_data;
+
 typedef HRESULT (WINAPI *SHGetKnownFolderPath_t)(const GUID &rfid, DWORD dwFlags, HANDLE hToken, PWSTR *ppszPath);
 typedef HRESULT (WINAPI *SHGetFolderPath_t)     (HWND hwndOwner, int nFolder, HANDLE hToken, DWORD dwFlags, LPWSTR pszPath);
 
-static QScopedPointer<KFMap>  g_known_folders_map;
-static QReadWriteLock         g_known_folders_lock;
-
 const QString &MUtils::OS::known_folder(known_folder_t folder_id)
 {
 	typedef enum { KF_FLAG_CREATE = 0x00008000 } kf_flags_t;
@@ -724,11 +724,11 @@ const QString &MUtils::OS::known_folder(known_folder_t folder_id)
 	QReadLocker readLock(&g_known_folders_lock);
 
 	//Already in cache?
-	if(!g_known_folders_map.isNull())
+	if(!g_known_folders_data.isNull())
 	{
-		if(g_known_folders_map->contains(folderId))
+		if(g_known_folders_data->contains(folderId))
 		{
-			return (*g_known_folders_map)[folderId];
+			return (*g_known_folders_data)[folderId];
 		}
 	}
 
@@ -737,18 +737,18 @@ const QString &MUtils::OS::known_folder(known_folder_t folder_id)
 	QWriteLocker writeLock(&g_known_folders_lock);
 
 	//Still not in cache?
-	if(!g_known_folders_map.isNull())
+	if(!g_known_folders_data.isNull())
 	{
-		if(g_known_folders_map->contains(folderId))
+		if(g_known_folders_data->contains(folderId))
 		{
-			return (*g_known_folders_map)[folderId];
+			return (*g_known_folders_data)[folderId];
 		}
 	}
 
 	//Initialize on first call
-	if(g_known_folders_map.isNull())
+	if(g_known_folders_data.isNull())
 	{
-		g_known_folders_map.reset(new QMap<size_t, QString>());
+		g_known_folders_data.reset(new QHash<size_t, QString>());
 	}
 
 	QString folderPath;
@@ -790,10 +790,11 @@ const QString &MUtils::OS::known_folder(known_folder_t folder_id)
 	//Update cache
 	if (!folderPath.isEmpty())
 	{
-		g_known_folders_map->insert(folderId, folderPath);
+		g_known_folders_data->insert(folderId, folderPath);
+		return (*g_known_folders_data)[folderId];
 	}
 
-	return folderPath;
+	return Internal::g_empty;
 }
 
 ///////////////////////////////////////////////////////////////////////////////