diff --git a/DDG4/plugins/Geant4SDActions.cpp b/DDG4/plugins/Geant4SDActions.cpp
index d50ef6f2ef4ae608f70cf1952cbc525418c16a45..7ff8e1ea4deab6e2ba7cee264a6a0d3e427abc16 100644
--- a/DDG4/plugins/Geant4SDActions.cpp
+++ b/DDG4/plugins/Geant4SDActions.cpp
@@ -97,7 +97,7 @@ namespace DD4hep {
 	    << " Post (" <<std::setw(24) << step->GetPostStepPoint()->GetMomentum() << ") "
 	    << std::endl;
 
-	std::cout << out;
+	std::cout << out.str();
 
 	return true;
       }