diff --git a/FileIO/Legacy/MeshIO.cpp b/FileIO/Legacy/MeshIO.cpp
index 12e1c4bd2e4f35061df86927b2657b81dc1d36fc..928003d92346a1320c6dadefd84c7c3b26efe2dd 100644
--- a/FileIO/Legacy/MeshIO.cpp
+++ b/FileIO/Legacy/MeshIO.cpp
@@ -42,6 +42,8 @@
 
 namespace FileIO
 {
+namespace Legacy {
+
 MeshIO::MeshIO()
 	: _mesh(NULL)
 {
@@ -292,5 +294,5 @@ void MeshIO::writeElements(std::vector<MeshLib::Element*> const& ele_vec,
 	}
 }
 
-
+}
 } // end namespace FileIO
diff --git a/FileIO/Legacy/MeshIO.h b/FileIO/Legacy/MeshIO.h
index 60a005f3995971ade5a533bc3752c651c3a10d05..f2d96ff6cf2ede6632ab3cb590fc6d4374dd9333 100644
--- a/FileIO/Legacy/MeshIO.h
+++ b/FileIO/Legacy/MeshIO.h
@@ -33,6 +33,8 @@ namespace MeshLib
 /// Interface for handling mesh files from OGS-5 and below. (*.msh files)
 namespace FileIO
 {
+namespace Legacy {
+
 class MeshIO : public Writer
 {
 public:
@@ -60,7 +62,8 @@ private:
 
 };  /* class */
 
-} /* namespace */
+}
+} /* namespace FileIO */
 
 #endif /* MESHIO_H_ */
 
diff --git a/FileIO/Legacy/OGSIOVer4.cpp b/FileIO/Legacy/OGSIOVer4.cpp
index 92f8bb4f725d5f2f3221e026080881939af2fa97..317ac15f7264ce9f6d8b5390e62bd4ca7b0f5135 100644
--- a/FileIO/Legacy/OGSIOVer4.cpp
+++ b/FileIO/Legacy/OGSIOVer4.cpp
@@ -48,6 +48,8 @@ using namespace GeoLib;
 
 namespace FileIO
 {
+namespace Legacy {
+
 /**************************************************************************
    GeoLib- Funktion: readPoints
    Aufgabe: Lesen der GLI Points und schreiben in einen Vector
@@ -745,4 +747,6 @@ void writeAllDataToGLIFileV4 (const std::string& fname, const GeoLib::GEOObjects
 	os << "#STOP" << "\n";
 	os.close ();
 }
-} // end namespace
+
+}
+} // end namespace FileIO
diff --git a/FileIO/Legacy/OGSIOVer4.h b/FileIO/Legacy/OGSIOVer4.h
index 22173cc9bc5e88522deb31defe8b8d65260ffeeb..e384aa9562cc50fad137dd816378abde99a3d8b0 100644
--- a/FileIO/Legacy/OGSIOVer4.h
+++ b/FileIO/Legacy/OGSIOVer4.h
@@ -33,6 +33,8 @@ class GEOObjects;
 
 namespace FileIO
 {
+namespace Legacy {
+
 /** Interface for handling geometry from OGS-5 and below (*.gli files) */
 
 /** Reads geometric objects from file in gli format */
@@ -46,6 +48,7 @@ void writeGLIFileV4 (const std::string& fname,
 /** Writes all geometric information to a gli-file */
 void writeAllDataToGLIFileV4 (const std::string& fname, const GeoLib::GEOObjects& geo);
 
-} // end namespace
+}
+} // end namespace FileIO
 
 #endif /* OGSIOVER4_H_ */
diff --git a/FileIO/XmlIO/Qt/XmlGspInterface.cpp b/FileIO/XmlIO/Qt/XmlGspInterface.cpp
index 3692b2b9076225337a52b21aa4fc9a3df33fa5d4..99f4c40da65784a97ce3e27d544d8b82846b4b04 100644
--- a/FileIO/XmlIO/Qt/XmlGspInterface.cpp
+++ b/FileIO/XmlIO/Qt/XmlGspInterface.cpp
@@ -152,7 +152,7 @@ int XmlGspInterface::write(std::ostream& stream)
 	     ++it)
 	{
 		// write mesh file
-		FileIO::MeshIO meshIO;
+		Legacy::MeshIO meshIO;
 		meshIO.setMesh(*it);
 		std::string fileName(path + (*it)->getName());
 		meshIO.writeToFile(fileName);
diff --git a/FileIO/readMeshFromFile.cpp b/FileIO/readMeshFromFile.cpp
index a1b1b4f2a5b420c516e148f3ee37c9559511a325..b4bc44ebc8302f94e07be1dd944159fcdfc75b41 100644
--- a/FileIO/readMeshFromFile.cpp
+++ b/FileIO/readMeshFromFile.cpp
@@ -36,12 +36,12 @@ MeshLib::Mesh* readMeshFromFile(const std::string &file_name)
 {
 	if (BaseLib::hasFileExtension("msh", file_name))
 	{
-		FileIO::MeshIO meshIO;
+		Legacy::MeshIO meshIO;
 		return meshIO.loadMeshFromFile(file_name);
 	}
 
 	if (BaseLib::hasFileExtension("vtu", file_name))
-		return FileIO::BoostVtuInterface::readVTUFile(file_name);
+		return BoostVtuInterface::readVTUFile(file_name);
 
 	ERR("readMeshFromFile(): Unknown mesh file format in file %s.", file_name.c_str());
 	return nullptr;
diff --git a/Gui/DataView/MshView.cpp b/Gui/DataView/MshView.cpp
index 953351e4b9cfc45c51d146238d0ab36d403b9271..78a89272456b53e9c64ded0b8733f4ff45e88e0d 100644
--- a/Gui/DataView/MshView.cpp
+++ b/Gui/DataView/MshView.cpp
@@ -237,14 +237,13 @@ int MshView::writeToFile() const
 			QFileInfo fi(fileName);
 			if (fi.suffix().toLower() == "vtu")
 			{
-				//FileIO::RapidVtuInterface vtkIO;
 				FileIO::BoostVtuInterface vtkIO;
 				vtkIO.setMesh(mesh);
 				vtkIO.writeToFile(fileName.toStdString().c_str());
 			}
 			if (fi.suffix().toLower() == "msh")
 			{
-				FileIO::MeshIO meshIO;
+				FileIO::Legacy::MeshIO meshIO;
 				meshIO.setMesh(mesh);
 				meshIO.writeToFile(fileName.toStdString().c_str());
 			}
diff --git a/Gui/mainwindow.cpp b/Gui/mainwindow.cpp
index e31ea87d9c94a810337c2c12f8a7bde9d26680b3..13fa4976ca87564e3e69b4c729cc77ca75047e86 100644
--- a/Gui/mainwindow.cpp
+++ b/Gui/mainwindow.cpp
@@ -533,7 +533,7 @@ void MainWindow::loadFile(ImportFileType::type t, const QString &fileName)
 		{
 			std::string unique_name;
 			std::vector<std::string> errors;
-			if (! readGLIFileV4(fileName.toStdString(), _project.getGEOObjects(), unique_name, errors)) {
+			if (! Legacy::readGLIFileV4(fileName.toStdString(), _project.getGEOObjects(), unique_name, errors)) {
 				for (size_t k(0); k<errors.size(); k++)
 					OGSError::box(QString::fromStdString(errors[k]));
 			}
diff --git a/SimpleTests/MeshTests/CollapseMeshNodes.cpp b/SimpleTests/MeshTests/CollapseMeshNodes.cpp
index f70432860131d3038b573865ee3ee94c6caa94be..f3db23d8088601904b6092cfd0284708ba8c8eb2 100644
--- a/SimpleTests/MeshTests/CollapseMeshNodes.cpp
+++ b/SimpleTests/MeshTests/CollapseMeshNodes.cpp
@@ -52,7 +52,7 @@ int main(int argc, char *argv[])
 
 	std::string fname (input_mesh_arg.getValue());
 
-	FileIO::MeshIO mesh_io;
+	FileIO::Legacy::MeshIO mesh_io;
 #ifndef WIN32
 	BaseLib::MemWatch mem_watch;
 	unsigned long mem_without_mesh (mem_watch.getVirtMemUsage());
diff --git a/SimpleTests/MeshTests/MeshSearchTest.cpp b/SimpleTests/MeshTests/MeshSearchTest.cpp
index cefe983a4c19ddd42c9ed00a7e2cbcb3a6d96890..66f9f7871f2bd57bbbf4a1bdb5ca2e429c587dd1 100644
--- a/SimpleTests/MeshTests/MeshSearchTest.cpp
+++ b/SimpleTests/MeshTests/MeshSearchTest.cpp
@@ -119,7 +119,7 @@ int main(int argc, char *argv[])
 
 	std::string fname (mesh_arg.getValue());
 
-	FileIO::MeshIO mesh_io;
+	FileIO::Legacy::MeshIO mesh_io;
 #ifndef WIN32
 	BaseLib::MemWatch mem_watch;
 	unsigned long mem_without_mesh (mem_watch.getVirtMemUsage());
diff --git a/Utils/FileConverter/GMSH2OGS.cpp b/Utils/FileConverter/GMSH2OGS.cpp
index 7b2fa23429a76a3247738a7e60709af4be25f250..687a8f9e1e2b9a3721b73aad41c2db3dfbe8bc20 100644
--- a/Utils/FileConverter/GMSH2OGS.cpp
+++ b/Utils/FileConverter/GMSH2OGS.cpp
@@ -40,7 +40,7 @@ int main (int argc, char* argv[])
 	}
 
 	tmp = argv[2];
-	MeshLib::Mesh* mesh (FileIO::MeshIO().loadMeshFromFile(tmp));
+	MeshLib::Mesh* mesh (FileIO::Legacy::MeshIO().loadMeshFromFile(tmp));
 
 	// *** create new mesh
 	tmp = argv[3];
@@ -52,7 +52,7 @@ int main (int argc, char* argv[])
 
 	tmp = argv[4];
 	std::cout << "writing mesh to file " << tmp << " ... " << std::flush;
-	FileIO::MeshIO mesh_io;
+	FileIO::Legacy::MeshIO mesh_io;
 	mesh_io.setMesh(mesh);
 	mesh_io.writeToFile (tmp);
 	std::cout << "ok" << std::endl;
diff --git a/Utils/FileConverter/VTK2OGS.cpp b/Utils/FileConverter/VTK2OGS.cpp
index 6d3aa8f6e38db7854a95a8afae8ded39b1f4ce37..6f110997be30c4394a56ebfd8f478f769a10c6ec 100644
--- a/Utils/FileConverter/VTK2OGS.cpp
+++ b/Utils/FileConverter/VTK2OGS.cpp
@@ -51,7 +51,7 @@ int main (int argc, char* argv[])
 	MeshLib::Mesh* mesh (FileIO::BoostVtuInterface::readVTUFile(mesh_in.getValue()));
 	INFO("Mesh read: %d nodes, %d elements.", mesh->getNNodes(), mesh->getNElements());
 
-	FileIO::MeshIO meshIO;
+	FileIO::Legacy::MeshIO meshIO;
 	meshIO.setMesh(mesh);
 	meshIO.writeToFile(mesh_out.getValue());
 
diff --git a/Utils/MeshEdit/moveMeshNodes.cpp b/Utils/MeshEdit/moveMeshNodes.cpp
index 2d24f30fb6e6c2b8ef730c00cc82700e08825824..e8dede492e3bbf499e7300518d4292cb2430a46e 100644
--- a/Utils/MeshEdit/moveMeshNodes.cpp
+++ b/Utils/MeshEdit/moveMeshNodes.cpp
@@ -185,7 +185,7 @@ int main (int argc, char* argv[])
 	}
 	/**** add other keywords here ****/
 
-	FileIO::MeshIO meshIO;
+	FileIO::Legacy::MeshIO meshIO;
 	meshIO.setMesh(mesh);
 	meshIO.setPrecision(9);
 	meshIO.writeToFile(msh_name.substr(0, msh_name.length()-4) + "_new.msh");
diff --git a/Utils/MeshEdit/removeMeshElements.cpp b/Utils/MeshEdit/removeMeshElements.cpp
index 64abe499358bf68776acc35edb954e8101b377f5..fd33d23e5e2c570b3040670f89e62a217cf780fe 100644
--- a/Utils/MeshEdit/removeMeshElements.cpp
+++ b/Utils/MeshEdit/removeMeshElements.cpp
@@ -177,7 +177,7 @@ int main (int argc, char* argv[])
 	MeshLib::Mesh* new_mesh(new MeshLib::Mesh(mesh->getName(), new_nodes, new_eles));
 
 	// write into a file
-	FileIO::MeshIO meshIO;
+	FileIO::Legacy::MeshIO meshIO;
 	meshIO.setMesh(new_mesh);
 	meshIO.writeToFile(mesh_out.getValue());
 
diff --git a/Utils/MeshEdit/removeMeshNodes.cpp b/Utils/MeshEdit/removeMeshNodes.cpp
index d4b46edd386c07df8dccf4e9b4203de3e1ac99d5..54d2b680d24d63a59581cc76df8daef99b710710 100644
--- a/Utils/MeshEdit/removeMeshNodes.cpp
+++ b/Utils/MeshEdit/removeMeshNodes.cpp
@@ -84,7 +84,7 @@ int main (int argc, char* argv[])
 	// remove nodes and write new file
 	MeshLib::Mesh* new_mesh = MeshLib::removeMeshNodes(*mesh, del_nodes);
 	
-	FileIO::MeshIO meshIO;
+	FileIO::Legacy::MeshIO meshIO;
 	meshIO.setMesh(mesh);
 	meshIO.setPrecision(9);
 	meshIO.writeToFile(msh_name.substr(0, msh_name.length()-4) + "_new.msh");
diff --git a/Utils/SimpleMeshCreation/createMeshElemPropertiesFromASCRaster.cpp b/Utils/SimpleMeshCreation/createMeshElemPropertiesFromASCRaster.cpp
index 32622a95e89c226be467135a66ebb5f31ea8a99b..543d6e49dd66ce15f6608c8436d087d951e68572 100644
--- a/Utils/SimpleMeshCreation/createMeshElemPropertiesFromASCRaster.cpp
+++ b/Utils/SimpleMeshCreation/createMeshElemPropertiesFromASCRaster.cpp
@@ -232,7 +232,7 @@ int main (int argc, char* argv[])
 			const_cast<MeshLib::Element*>(dest_mesh->getElement(dest_perm[k]))->setValue(k);
 		}
 
-		FileIO::MeshIO mesh_writer;
+		FileIO::Legacy::MeshIO mesh_writer;
 		mesh_writer.setPrecision(12);
 		mesh_writer.setMesh(dest_mesh);
 		mesh_writer.writeToFile(out_mesh_arg.getValue());
diff --git a/Utils/SimpleMeshCreation/generateStructuredQuadMesh.cpp b/Utils/SimpleMeshCreation/generateStructuredQuadMesh.cpp
index 571faee014be8dc8b30ce2c2f919b0b3e8d42e31..3a3fde09f042ad475d44406fc4f84076b9e24c6e 100644
--- a/Utils/SimpleMeshCreation/generateStructuredQuadMesh.cpp
+++ b/Utils/SimpleMeshCreation/generateStructuredQuadMesh.cpp
@@ -55,7 +55,7 @@ int main (int argc, char* argv[])
 
 	delete [] values;
 
-	FileIO::MeshIO mesh_writer;
+	FileIO::Legacy::MeshIO mesh_writer;
 	mesh_writer.setMesh(mesh);
 	mesh_writer.setPrecision(12);
 	mesh_writer.writeToFile(mesh_arg.getValue());