diff --git a/Modules/IGT/TrackingDevices/mitkPolhemusTrackerTypeInformation.cpp b/Modules/IGT/TrackingDevices/mitkPolhemusTrackerTypeInformation.cpp
index 4efd7f2596..e040fa025b 100644
--- a/Modules/IGT/TrackingDevices/mitkPolhemusTrackerTypeInformation.cpp
+++ b/Modules/IGT/TrackingDevices/mitkPolhemusTrackerTypeInformation.cpp
@@ -1,70 +1,70 @@
 /*===================================================================
 
 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.
 
 ===================================================================*/
 
 #include "mitkPolhemusTrackerTypeInformation.h"
 
 #include "mitkPolhemusTrackingDevice.h"
 
 namespace mitk
 {
   std::string PolhemusTrackerTypeInformation::GetTrackingDeviceName()
   {
     return "Polhemus tracker";
   }
 
   TrackingDeviceData PolhemusTrackerTypeInformation::GetDeviceDataPolhemusTrackerLiberty()
   {
     TrackingDeviceData data = { PolhemusTrackerTypeInformation::GetTrackingDeviceName(), "Polhemus Liberty Tracker", "cube", "X" };
     return data;
   }
 
   PolhemusTrackerTypeInformation::PolhemusTrackerTypeInformation()
   {
     m_DeviceName = PolhemusTrackerTypeInformation::GetTrackingDeviceName();
     m_TrackingDeviceData.push_back(GetDeviceDataPolhemusTrackerLiberty());
   }
 
   PolhemusTrackerTypeInformation::~PolhemusTrackerTypeInformation()
   {
   }
 
   mitk::TrackingDeviceSource::Pointer PolhemusTrackerTypeInformation::CreateTrackingDeviceSource(
     mitk::TrackingDevice::Pointer trackingDevice,
     mitk::NavigationToolStorage::Pointer navigationTools,
     std::string* errorMessage,
     std::vector<int>* toolCorrespondencesInToolStorage)
   {
     mitk::TrackingDeviceSource::Pointer returnValue = mitk::TrackingDeviceSource::New();
     mitk::PolhemusTrackingDevice::Pointer thisDevice = dynamic_cast<mitk::PolhemusTrackingDevice*>(trackingDevice.GetPointer());
     *toolCorrespondencesInToolStorage = std::vector<int>();
     //add the tools to the tracking device
-    for (int i = 0; i < navigationTools->GetToolCount(); i++)
+    for (unsigned int i = 0; i < navigationTools->GetToolCount(); i++)
     {
       mitk::NavigationTool::Pointer thisNavigationTool = navigationTools->GetTool(i);
       toolCorrespondencesInToolStorage->push_back(i);
       bool toolAddSuccess = thisDevice->AddTool(thisNavigationTool->GetToolName().c_str(), std::stoi(thisNavigationTool->GetIdentifier()));
       if (!toolAddSuccess)
       {
         //todo error handling
         errorMessage->append("Can't add tool, is the toolfile valid?");
         return NULL;
       }
       thisDevice->GetTool(i)->SetToolTip(thisNavigationTool->GetToolTipPosition(), thisNavigationTool->GetToolTipOrientation());
     }
     returnValue->SetTrackingDevice(thisDevice);
     return returnValue;
   }
 }