diff --git a/DynamicModel.cc b/DynamicModel.cc
index f926d32e6bbd602c8611679e0a92d34459ee9f5d..070fe0ce4e1f325d0da831aec7fd61f84a6331f2 100644
--- a/DynamicModel.cc
+++ b/DynamicModel.cc
@@ -1836,6 +1836,7 @@ DynamicModel::writeSparseDynamicMFile(const string &dynamic_basename, const stri
   bool open_par = false;
 
   mDynamicModelFile << "function [varargout] = " << dynamic_basename << "(options_, M_, oo_, varargin)\n";
+  mDynamicModelFile << "  varargout{1} = NaN;\n";
   mDynamicModelFile << "  g2=[];g3=[];\n";
   //Temporary variables declaration
   OK = true;