Index: Ringtoets/Revetment/src/Ringtoets.Revetment.Service/WaveConditionsCalculationServiceBase.cs
===================================================================
diff -u -rbd73023d5f8926a411da214fb5ce522056a0e30a -re07044ef611f4a005447703ffba9f24b7c5acb90
--- Ringtoets/Revetment/src/Ringtoets.Revetment.Service/WaveConditionsCalculationServiceBase.cs	(.../WaveConditionsCalculationServiceBase.cs)	(revision bd73023d5f8926a411da214fb5ce522056a0e30a)
+++ Ringtoets/Revetment/src/Ringtoets.Revetment.Service/WaveConditionsCalculationServiceBase.cs	(.../WaveConditionsCalculationServiceBase.cs)	(revision e07044ef611f4a005447703ffba9f24b7c5acb90)
@@ -214,6 +214,7 @@
             calculator = HydraRingCalculatorFactory.Instance.CreateWaveConditionsCosineCalculator(hlcdDirectory, ringId);
             WaveConditionsCosineCalculationInput calculationInput = CreateInput(waterLevel, a, b, c, norm, input);
 
+            var exceptionThrown = false;
             try
             {
                 calculator.Calculate(calculationInput);
@@ -227,17 +228,48 @@
             {
                 if (!Canceled)
                 {
-                    log.ErrorFormat(CultureInfo.CurrentCulture,
-                                    Resources.WaveConditionsCalculationService_VerifyWaveConditionsCalculationOutput_Error_in_wave_conditions_calculation_0_for_waterlevel_1,
-                                    name,
-                                    waterLevel);
+                    var lastErrorContent = calculator.LastErrorContent;
+                    if (string.IsNullOrEmpty(lastErrorContent))
+                    {
+                        log.ErrorFormat(CultureInfo.CurrentCulture,
+                                        Resources.WaveConditionsCalculationService_CalculateWaterLevel_Unexplained_error_in_wave_conditions_calculation_0_for_waterlevel_1,
+                                        name,
+                                        waterLevel);
+                    }
+                    else
+                    {
+                        log.ErrorFormat(CultureInfo.CurrentCulture,
+                                        Resources.WaveConditionsCalculationService_CalculateWaterLevel_Error_in_wave_conditions_calculation_0_for_waterlevel_1_click_details_for_last_error_2,
+                                        name,
+                                        waterLevel,
+                                        lastErrorContent);
+                    }
+
+                    exceptionThrown = true;
                     throw;
                 }
                 return null;
             }
             finally
             {
-                log.InfoFormat(Resources.WaveConditionsCalculationService_CalculateWaterLevel_Calculation_temporary_directory_can_be_found_on_location_0, calculator.OutputDirectory);
+                try
+                {
+                    var lastErrorContent = calculator.LastErrorContent;
+                    if (!exceptionThrown && !string.IsNullOrEmpty(lastErrorContent))
+                    {
+                        log.ErrorFormat(CultureInfo.CurrentCulture,
+                                        Resources.WaveConditionsCalculationService_CalculateWaterLevel_Error_in_wave_conditions_calculation_0_for_waterlevel_1_click_details_for_last_error_2,
+                                        name,
+                                        waterLevel,
+                                        lastErrorContent);
+
+                        throw new HydraRingFileParserException(lastErrorContent);
+                    }
+                }
+                finally
+                {
+                    log.InfoFormat(Resources.WaveConditionsCalculationService_CalculateWaterLevel_Calculation_temporary_directory_can_be_found_on_location_0, calculator.OutputDirectory);
+                }
             }
         }