Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/DikesDesign/DesignCalculator.cs
===================================================================
diff -u -r2799 -r3403
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/DikesDesign/DesignCalculator.cs	(.../DesignCalculator.cs)	(revision 2799)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/DikesDesign/DesignCalculator.cs	(.../DesignCalculator.cs)	(revision 3403)
@@ -81,9 +81,10 @@
                     for (int subSoilScenarioIndex = 0; subSoilScenarioIndex < location.Segment.SoilProfileProbabilities.Count; subSoilScenarioIndex++)
                     {
                         // Check if the subSoilScenario is applicable for the failuremechanism that is being calculated
-                        if (location.Segment.SoilProfileProbabilities[subSoilScenarioIndex].SegmentFailureMechanismType.Value.In(
+                        if (location.Segment.SoilProfileProbabilities[subSoilScenarioIndex].SegmentFailureMechanismType.HasValue && 
+                            (location.Segment.SoilProfileProbabilities[subSoilScenarioIndex].SegmentFailureMechanismType.Value.In(
                             ConversionHelper.ConvertToSegmentFailureMechanismType(damProjectData.DamProjectCalculationSpecification.CurrentSpecification.FailureMechanismSystemType),
-                            SegmentFailureMechanismType.All))
+                            SegmentFailureMechanismType.All)))
                         {
                             var soiProfileProbability = location.Segment.SoilProfileProbabilities[subSoilScenarioIndex];
                             for (int designScenarioIndex = 0; designScenarioIndex < location.Scenarios.Count; designScenarioIndex++)