diff --git a/NPSimulation/Core/EventAction.cc b/NPSimulation/Core/EventAction.cc
index 5f091b942f7f0e4d351163325cc1078aa0c06321..1f35d8ed710a85b453fceea35d3f4eaaec53dacc 100644
--- a/NPSimulation/Core/EventAction.cc
+++ b/NPSimulation/Core/EventAction.cc
@@ -87,6 +87,8 @@ void EventAction::SaveRandomGeneratorInitialState(){
 
     CLHEP::HepRandom::saveFullState(m_Geant4RandomFullState);
     m_G4State=m_Geant4RandomFullState.str();
+    m_Geant4RandomFullState.str("");
+    m_Geant4RandomFullState.clear();
 }
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......