diff --git a/Modules/Persistence/mitkPersistenceActivator.cpp b/Modules/Persistence/mitkPersistenceActivator.cpp
index fd16688195..2af8ef6b36 100644
--- a/Modules/Persistence/mitkPersistenceActivator.cpp
+++ b/Modules/Persistence/mitkPersistenceActivator.cpp
@@ -1,88 +1,93 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 #ifndef mitkPersistenceActivator_h
 #define mitkPersistenceActivator_h
 
 // Microservices
 #include <usModuleActivator.h>
 #include "mitkPersistenceService.h"
 #include <usServiceRegistration.h>
 
 namespace mitk
 {
     ///
     /// installs the PersistenceService
     /// runs all initial commands (setting env paths etc)
     ///
     class PersistenceActivator : public us::ModuleActivator
     {
     public:
+        PersistenceActivator()
+        {
+        }
 
         void Load(us::ModuleContext* context)
         {
           MITK_DEBUG << "PersistenceActivator::Load";
 
           mitk::IPersistenceService* persistenceService = 0;
           us::ServiceReference<mitk::IPersistenceService> persistenceServiceRef
             = context->GetServiceReference<mitk::IPersistenceService>();
           if( persistenceServiceRef )
           {
             persistenceService = dynamic_cast<mitk::IPersistenceService*> ( context->GetService<mitk::IPersistenceService>(persistenceServiceRef) );
           }
 
           bool instanceAlreadyAdded = persistenceService != 0;
           if( instanceAlreadyAdded )
             instanceAlreadyAdded = dynamic_cast<mitk::PersistenceService*>(persistenceService) != 0;
 
           if( instanceAlreadyAdded == false )
           {
             // Registering PersistenceService as MicroService
             m_PersistenceService = itk::SmartPointer<mitk::PersistenceService>(new PersistenceService());
             us::ServiceProperties _PersistenceServiceProps;
             _PersistenceServiceProps["Name"] = std::string("PersistenceService");
 
             m_PersistenceServiceRegistration = context->RegisterService<mitk::IPersistenceService>(m_PersistenceService, _PersistenceServiceProps);
 
           }
           else
           {
             MITK_ERROR << "Another Persistence instance already installed. Library was loaded twice. Please check configuration!";
           }
         }
 
         void Unload(us::ModuleContext* context)
         {
+          if( m_PersistenceService.IsNull() )
+            return;
+
           MITK_DEBUG("PersistenceActivator") << "PersistenceActivator::Unload";
           MITK_DEBUG("PersistenceActivator") << "m_PersistenceService GetReferenceCount " << m_PersistenceService->GetReferenceCount();
 
+          //m_PersistenceServiceRegistration.Unregister();
           m_PersistenceService->Unitialize();
-
-          m_PersistenceServiceRegistration.Unregister();
           m_PersistenceService->Delete();
         }
 
         virtual ~PersistenceActivator()
         {
         }
 
     private:
         itk::SmartPointer<mitk::PersistenceService> m_PersistenceService;
         us::ServiceRegistration<mitk::IPersistenceService> m_PersistenceServiceRegistration;
     };
 }
 
 US_EXPORT_MODULE_ACTIVATOR(Persistence, mitk::PersistenceActivator)
 #endif