diff --git a/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MDT_RawDataProviderTool.h b/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MDT_RawDataProviderTool.h
index ee6302337ed2a36e4ed501164237ea1c6c6ae19f..a23afd654652b521bfa439f3ffe934e116e4cf0b 100644
--- a/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MDT_RawDataProviderTool.h
+++ b/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MDT_RawDataProviderTool.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONMDTCNVTOOLS_MUONMDTRAWDATAPROVIDERTOOL_H
@@ -39,7 +39,7 @@ class ATLAS_NOT_THREAD_SAFE MDT_RawDataProviderTool : virtual public IMuonRawDat
   virtual StatusCode finalize  ();
   
   /** Convert method - declared in Muon::IMuonRdoToPrepDataTool*/
-  virtual StatusCode convert( const std::vector<const OFFLINE_FRAGMENTS_NAMESPACE::ROBFragment*>& vecRobs);
+  virtual StatusCode convert ATLAS_NOT_THREAD_SAFE ( const std::vector<const OFFLINE_FRAGMENTS_NAMESPACE::ROBFragment*>& vecRobs);
   virtual StatusCode convert( const std::vector<const OFFLINE_FRAGMENTS_NAMESPACE::ROBFragment*>& vecRobs, const std::vector<IdentifierHash>&);
   /** the new ones */
   virtual StatusCode convert(); //!< for the entire event 
diff --git a/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.cxx b/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.cxx
index 1c11ae58838e5bd6ec8088a563610350ad2a6800..0506b43b1a26af45529ddc09188a0fc425e6e298 100644
--- a/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.cxx
+++ b/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.cxx
@@ -21,7 +21,7 @@ StatusCode Muon::MdtRdoToPrepDataTool::initialize()
   return StatusCode::SUCCESS;
 }
 
-Muon::MdtRdoToPrepDataTool::SetupMdtPrepDataContainerStatus Muon::MdtRdoToPrepDataTool::setupMdtPrepDataContainer ATLAS_NOT_THREAD_SAFE()
+Muon::MdtRdoToPrepDataTool::SetupMdtPrepDataContainerStatus Muon::MdtRdoToPrepDataTool::setupMdtPrepDataContainer()
 {
   if(!evtStore()->contains<Muon::MdtPrepDataContainer>(m_mdtPrepDataContainerKey.key())){	 
     m_fullEventDone=false;
diff --git a/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.h b/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.h
index 1ea69192d30d15b768039d8daf7a2c2822630e1c..9b0a3fc60de81f8add488c9d773095432c582348 100644
--- a/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.h
+++ b/MuonSpectrometer/MuonCnv/MuonMDT_CnvTools/src/MdtRdoToPrepDataTool.h
@@ -6,6 +6,7 @@
 #define MUONMdtRdoToPrepDataTool_H
      
 #include "MdtRdoToPrepDataToolCore.h"
+#include "CxxUtils/checker_macros.h"
 
 namespace Muon 
 {
@@ -21,7 +22,7 @@ namespace Muon
       @author  Edward Moyse <Edward.Moyse@cern.ch>
   */  
 
-  class MdtRdoToPrepDataTool : virtual public MdtRdoToPrepDataToolCore
+  class ATLAS_NOT_THREAD_SAFE MdtRdoToPrepDataTool : virtual public MdtRdoToPrepDataToolCore
   {
   public:
     MdtRdoToPrepDataTool(const std::string&,const std::string&,const IInterface*);