diff --git a/libsrc/general/ngexception.cpp b/libsrc/general/ngexception.cpp
index 2496f6b3..6bcd2cc9 100644
--- a/libsrc/general/ngexception.cpp
+++ b/libsrc/general/ngexception.cpp
@@ -13,7 +13,7 @@ namespace netgen
 
 
   NgException :: NgException (const string & s) 
-    : what(s)
+    : m_what(s)
   {
     ; 
   }
@@ -27,7 +27,7 @@ namespace netgen
   /// append string to description
   void NgException :: Append (const string & s)
   { 
-    what += s; 
+    m_what += s;
   }
 
 }
diff --git a/libsrc/general/ngexception.hpp b/libsrc/general/ngexception.hpp
index 70dc0a4a..6e06498c 100644
--- a/libsrc/general/ngexception.hpp
+++ b/libsrc/general/ngexception.hpp
@@ -11,10 +11,10 @@ namespace netgen
 {
 
 /// Base class for all ng exceptions
-class NgException 
+class NgException : public std::exception
 {
   /// verbal description of exception
-  string what;
+  string m_what;
 public:
   ///
   DLL_HEADER NgException (const string & s);
@@ -26,7 +26,8 @@ public:
   //  void Append (const char * s);
   
   /// verbal description of exception
-  const string & What() const { return what; }
+  const string & What() const { return m_what; }
+  virtual const char* what() const noexcept override { return m_what.c_str(); }
 };
 }
 
diff --git a/libsrc/interface/nginterface.cpp b/libsrc/interface/nginterface.cpp
index 39ddacd3..edce3398 100644
--- a/libsrc/interface/nginterface.cpp
+++ b/libsrc/interface/nginterface.cpp
@@ -118,6 +118,11 @@ void Ng_LoadMeshFromStream ( istream & input )
 
 void Ng_LoadMesh (const char * filename)
 {
+  {
+      auto infile = ifstream (filename);
+      if(!infile.good())
+          throw NgException(string("Error opening file ") + filename);
+  }
 #ifdef PARALLEL
   MPI_Comm_size(MPI_COMM_WORLD, &ntasks);
   MPI_Comm_rank(MPI_COMM_WORLD, &id);
diff --git a/libsrc/meshing/python_mesh.cpp b/libsrc/meshing/python_mesh.cpp
index aaed8073..5db83ed1 100644
--- a/libsrc/meshing/python_mesh.cpp
+++ b/libsrc/meshing/python_mesh.cpp
@@ -52,6 +52,7 @@ static Transformation<3> global_trafo(Vec<3> (0,0,0));
 
 DLL_HEADER void ExportNetgenMeshing(py::module &m) 
 {
+  py::register_exception<NgException>(m, "NgException");
   m.attr("_netgen_executable_started") = py::cast(netgen::netgen_executable_started);
   string script;
   const char ** hcp = ngscript;