Index: Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Service/DuneErosionBoundaryCalculationActivity.cs
===================================================================
diff -u -r628518ea0f08da7e3d5a06e3084d03c757b06e3f -r847c9de88eea68ff8b52d5111f2d09a0199302d8
--- Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Service/DuneErosionBoundaryCalculationActivity.cs	(.../DuneErosionBoundaryCalculationActivity.cs)	(revision 628518ea0f08da7e3d5a06e3084d03c757b06e3f)
+++ Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Service/DuneErosionBoundaryCalculationActivity.cs	(.../DuneErosionBoundaryCalculationActivity.cs)	(revision 847c9de88eea68ff8b52d5111f2d09a0199302d8)
@@ -73,6 +73,12 @@
 
         protected override void PerformCalculation()
         {
+            if (duneLocation.Output != null)
+            {
+                State = ActivityState.Skipped;
+                return;
+            }
+
             calculationService.Calculate(duneLocation,
                                          failureMechanism,
                                          assessmentSection,