Index: Riskeer/Common/src/Riskeer.Common.Service/Structures/StructuresCalculationServiceBase.cs
===================================================================
diff -u -r0ded44e239c0e46f08dde2696ffc6d3c81ff337c -r9d221c80e414846f872fdfcef0683b6bf053b404
--- Riskeer/Common/src/Riskeer.Common.Service/Structures/StructuresCalculationServiceBase.cs	(.../StructuresCalculationServiceBase.cs)	(revision 0ded44e239c0e46f08dde2696ffc6d3c81ff337c)
+++ Riskeer/Common/src/Riskeer.Common.Service/Structures/StructuresCalculationServiceBase.cs	(.../StructuresCalculationServiceBase.cs)	(revision 9d221c80e414846f872fdfcef0683b6bf053b404)
@@ -315,24 +315,28 @@
         /// enum value is encountered.</exception>
         private static string[] ValidateInput(TStructureInput input, IAssessmentSection assessmentSection)
         {
-            var validationResults = new List<string>();
-
-            string connectionValidationProblem = HydraulicBoundaryDataConnectionValidator.Validate(assessmentSection.HydraulicBoundaryData);
-            if (!string.IsNullOrEmpty(connectionValidationProblem))
+            if (input.HydraulicBoundaryLocation == null)
             {
-                validationResults.Add(connectionValidationProblem);
+                return new[]
+                {
+                    Resources.CalculationService_ValidateInput_No_hydraulic_boundary_location_selected
+                };
             }
 
-            if (validationResults.Any())
-            {
-                return validationResults.ToArray();
-            }
+            string connectionValidationProblem = HydraulicBoundaryDataConnectionValidator.Validate(
+                assessmentSection.HydraulicBoundaryData,
+                input.HydraulicBoundaryLocation);
 
-            if (input.HydraulicBoundaryLocation == null)
+            if (!string.IsNullOrEmpty(connectionValidationProblem))
             {
-                validationResults.Add(Resources.CalculationService_ValidateInput_No_hydraulic_boundary_location_selected);
+                return new[]
+                {
+                    connectionValidationProblem
+                };
             }
 
+            var validationResults = new List<string>();
+
             if (input.Structure == null)
             {
                 validationResults.Add(Resources.StructuresCalculationService_ValidateInput_No_Structure_selected);