diff --git a/BaseLib/FileTools.cpp b/BaseLib/FileTools.cpp
index 6f60be1b85870b6057b9f3f98029a63958dafc87..75525033b2c0b7e214e213d0e3144b976423dda2 100644
--- a/BaseLib/FileTools.cpp
+++ b/BaseLib/FileTools.cpp
@@ -141,11 +141,11 @@ std::string extractPath(std::string const& pathname)
         return "";
     return pathname.substr(0, pos + 1);
 }
-static const char * pathSeparator =
+static const char pathSeparator =
 #ifdef _WIN32
-                            "\\";
+                            '\\';
 #else
-                            "/";
+                            '/';
 #endif
 
 std::string appendPathSeparator(std::string const& path)
@@ -157,12 +157,18 @@ std::string appendPathSeparator(std::string const& path)
 
 std::string joinPaths(std::string const& pathA, std::string const& pathB)
 {
-    std::string tmpB(pathB);
-    if(tmpB.substr(0, 1) == ".")
-        tmpB = tmpB.substr(1);
-    if(tmpB.substr(0, 1) == pathSeparator)
-        tmpB = tmpB.substr(1);
-    return appendPathSeparator(pathA) + tmpB;
+    if (pathA.empty())
+        return pathB;
+
+    if (pathB.empty())
+        return pathA;
+
+    if (pathB.front() == pathSeparator) {
+        auto const tmpB = pathB.substr(1);
+        return appendPathSeparator(pathA) + tmpB;
+    } else {
+        return appendPathSeparator(pathA) + pathB;
+    }
 }
 
 } // end namespace BaseLib
diff --git a/MeshLib/IO/VtkIO/VtuInterface.cpp b/MeshLib/IO/VtkIO/VtuInterface.cpp
index 95b4343667ee410e757cff7584a4ef6069be1a29..516e37ae87c069cba84107cd7b9407317e479f79 100644
--- a/MeshLib/IO/VtkIO/VtuInterface.cpp
+++ b/MeshLib/IO/VtkIO/VtuInterface.cpp
@@ -77,12 +77,17 @@ bool VtuInterface::writeToFile(std::string const &file_name)
     // and PETSC_COMM_WORLD should be replaced with the argument.
     int mpi_rank;
     MPI_Comm_rank(PETSC_COMM_WORLD, &mpi_rank);
-    std::string file_name_base = boost::erase_last_copy(file_name, ".vtu");
+    auto const file_name_base = boost::erase_last_copy(file_name, ".vtu");
+
+    auto const dirname = BaseLib::extractPath(file_name_base);
+    auto basename = BaseLib::extractBaseName(file_name_base);
 
     // Since the pvtu writing function drops all letters from the letter of '.'.
-    std::replace(file_name_base.begin(), file_name_base.end(), '.', '_');
+    std::replace(basename.begin(), basename.end(), '.', '_');
+
+    auto const vtu_file_name = BaseLib::joinPaths(dirname, basename);
 
-    const std::string file_name_rank = file_name_base + "_"
+    const std::string file_name_rank = vtu_file_name + "_"
                                        + std::to_string(mpi_rank) + ".vtu";
     bool vtu_status_i = writeVTU<vtkXMLUnstructuredGridWriter>(file_name_rank);
     bool vtu_status = false;
@@ -93,7 +98,7 @@ bool VtuInterface::writeToFile(std::string const &file_name)
     bool pvtu_status = false;
     if (mpi_rank == 0)
     {
-        pvtu_status = writeVTU<vtkXMLPUnstructuredGridWriter>(file_name_base + ".pvtu", mpi_size);
+        pvtu_status = writeVTU<vtkXMLPUnstructuredGridWriter>(vtu_file_name + ".pvtu", mpi_size);
     }
     MPI_Bcast(&pvtu_status, 1, MPI_C_BOOL, 0, PETSC_COMM_WORLD);
 
diff --git a/Tests/BaseLib/TestFilePathStringManipulation.cpp b/Tests/BaseLib/TestFilePathStringManipulation.cpp
index a4e59b51e6213554ae0bae2a113d00c975835fea..1680f4884fc00ef445ddbaee8ef3fcdd19d310ad 100644
--- a/Tests/BaseLib/TestFilePathStringManipulation.cpp
+++ b/Tests/BaseLib/TestFilePathStringManipulation.cpp
@@ -391,12 +391,13 @@ TEST(BaseLib, ExtractPathUnix)
 TEST(BaseLib, JoinPaths)
 {
 #if _WIN32
-    ASSERT_EQ ( "\\path\\path", BaseLib::joinPaths("\\path", "path") );
     ASSERT_EQ ( "\\path\\path", BaseLib::joinPaths("\\path", "\\path") );
-    ASSERT_EQ ( "\\path\\path", BaseLib::joinPaths("\\path", ".\\path") );
+    ASSERT_EQ ( "\\path\\path", BaseLib::joinPaths("\\path\\", "\\path") );
+    ASSERT_EQ ( "\\path\\.\\path", BaseLib::joinPaths("\\path", ".\\path") );
 #else
-    ASSERT_EQ ( "/path/path", BaseLib::joinPaths("/path", "path") );
     ASSERT_EQ ( "/path/path", BaseLib::joinPaths("/path", "/path") );
-    ASSERT_EQ ( "/path/path", BaseLib::joinPaths("/path", "./path") );
+    ASSERT_EQ ( "/path/path", BaseLib::joinPaths("/path/", "/path") );
+    ASSERT_EQ ( "/path/./path", BaseLib::joinPaths("/path", "./path") );
+    ASSERT_EQ ( "/path", BaseLib::joinPaths("/", "path") );
 #endif
 }