diff --git a/trunk/paradiseo-moeo/src/metric/moeoHyperVolumeDifferenceMetric.h b/trunk/paradiseo-moeo/src/metric/moeoHyperVolumeDifferenceMetric.h
index 8ca9fce1a..c34cb5dd8 100644
--- a/trunk/paradiseo-moeo/src/metric/moeoHyperVolumeDifferenceMetric.h
+++ b/trunk/paradiseo-moeo/src/metric/moeoHyperVolumeDifferenceMetric.h
@@ -135,7 +135,8 @@ class moeoHyperVolumeDifferenceMetric : public moeoVectorVsVectorBinaryMetric <
      */
     void setup(const std::vector < ObjectiveVector > & _set1, const std::vector < ObjectiveVector > & _set2){
     	if(_set1.size() < 1 || _set2.size() < 1)
-    		throw("Error in moeoHyperVolumeUnaryMetric::setup -> argument1: vector<ObjectiveVector> size must be greater than 0");
+    		std::cout << "Warning!!! In moeoHyperVolumeUnaryMetric::setup -> argument1: vector<ObjectiveVector> size must be greater than 0" << std::endl;
+    		//throw("Error in moeoHyperVolumeUnaryMetric::setup -> argument1: vector<ObjectiveVector> size must be greater than 0");
     	else{
 	        double min, max;
 	        unsigned int nbObj=ObjectiveVector::Traits::nObjectives();