diff --git a/VECTO3GUI2020/ViewModel/MultiStage/Implementation/MultistageAuxiliariesViewModel.cs b/VECTO3GUI2020/ViewModel/MultiStage/Implementation/MultistageAuxiliariesViewModel.cs
index 1a6f3eae235a8b2be9cd23c79887dc5a4be87e5c..3b762b2fa2417a2ba5c7924235905c64392b2b0d 100644
--- a/VECTO3GUI2020/ViewModel/MultiStage/Implementation/MultistageAuxiliariesViewModel.cs
+++ b/VECTO3GUI2020/ViewModel/MultiStage/Implementation/MultistageAuxiliariesViewModel.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
@@ -186,10 +187,11 @@ namespace VECTO3GUI2020.ViewModel.MultiStage.Implementation
 			SystemConfiguration = componentsAuxiliaryInputData.HVACAux?.SystemConfiguration;
 			HeatPumpTypeDriverCompartment = componentsAuxiliaryInputData.HVACAux?.HeatPumpTypeDriverCompartment;
 			HeatPumpModeDriverCompartment = componentsAuxiliaryInputData.HVACAux?.HeatPumpModeDriverCompartment;
-			HeatPumpConfigurationsPassenger.Clear();
-			if (componentsAuxiliaryInputData.HVACAux?.HeatPumpPassengerCompartments != null)
+			HeatPumpConfigurationsPassenger = null;
+			HeatPumpConfigurationsPassenger = new ObservableCollection<HeatPumpConfiguration>();
+			if (componentsAuxiliaryInputData?.HVACAux?.HeatPumpPassengerCompartments != null)
 			{
-				foreach (var (heatPumpType, heatPumpMode) in componentsAuxiliaryInputData.HVACAux?.HeatPumpPassengerCompartments)
+				foreach (var (heatPumpType, heatPumpMode) in componentsAuxiliaryInputData.HVACAux.HeatPumpPassengerCompartments)
 				{
 					HeatPumpConfigurationsPassenger.Add(new HeatPumpConfiguration()
 					{
@@ -247,6 +249,7 @@ namespace VECTO3GUI2020.ViewModel.MultiStage.Implementation
 					nameof(IHVACBusAuxiliariesDeclarationData.AdjustableCoolantThermostat),
 					nameof(IHVACBusAuxiliariesDeclarationData.EngineWasteGasHeatExchanger)
 				});
+
 				foreach (var propInfo in HVACinterfaceProperties) {
 					if (notImplemented.Contains(propInfo.Name)) continue;
 					hasValues = hasValues || propInfo.GetValue(this) != null;
@@ -383,14 +386,16 @@ namespace VECTO3GUI2020.ViewModel.MultiStage.Implementation
 		public IList<Tuple<HeatPumpType, HeatPumpMode>> HeatPumpPassengerCompartments{
 			get
 			{
-				var list = new List<Tuple<HeatPumpType, HeatPumpMode>>();
+				IList<Tuple<HeatPumpType,HeatPumpMode>> list = null;
 				if (HeatPumpConfigurationsPassenger != null) {
+					list = new List<Tuple<HeatPumpType, HeatPumpMode>>();
 					foreach (var heatPumpConfiguration in HeatPumpConfigurationsPassenger)
 					{
 						list.Add(new Tuple<HeatPumpType, HeatPumpMode>((HeatPumpType)heatPumpConfiguration.HeatPumpType, (HeatPumpMode)heatPumpConfiguration.HeatPumpMode));
 					}
 				}
-				
+
+
 				return list;
 			}
 		}
diff --git a/Vecto3GUI2020Test/UI/UITests.cs b/Vecto3GUI2020Test/UI/UITests.cs
index 797da3c10a0538eeb28517b10764df6a37926fdc..969b9c5a054b5ede41a07d6416946dee45b1bfdd 100644
--- a/Vecto3GUI2020Test/UI/UITests.cs
+++ b/Vecto3GUI2020Test/UI/UITests.cs
@@ -25,7 +25,7 @@ namespace Vecto3GUI2020Test
             Setup(TestContext.CurrentContext);
 		}
 
-
+		[Ignore("ignored UI test")]
 		[Test]
 		public void LoadFileSession()
 		{