Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationService.cs
===================================================================
diff -u -re14ae58fe3639b6850b6e0bece9bbaa8a6267fdc -r9cf89e3f60d17b61c5ef1ba1c4c7e18ca0c9b2f4
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationService.cs	(.../GrassCoverErosionInwardsCalculationService.cs)	(revision e14ae58fe3639b6850b6e0bece9bbaa8a6267fdc)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationService.cs	(.../GrassCoverErosionInwardsCalculationService.cs)	(revision 9cf89e3f60d17b61c5ef1ba1c4c7e18ca0c9b2f4)
@@ -772,13 +772,15 @@
         {
             var validationResults = new List<string>();
 
-            string databaseFilePathValidationProblem = HydraulicBoundaryDatabaseHelper.ValidatePathForCalculation(assessmentSection.HydraulicBoundaryDatabase.FilePath);
+            string preprocessorDirectory = assessmentSection.HydraulicBoundaryDatabase.EffectivePreprocessorDirectory();
+            string databaseFilePathValidationProblem = HydraulicBoundaryDatabaseHelper.ValidatePathForCalculation(assessmentSection.HydraulicBoundaryDatabase.FilePath,
+                                                                                                                  preprocessorDirectory);
             if (!string.IsNullOrEmpty(databaseFilePathValidationProblem))
             {
                 validationResults.Add(databaseFilePathValidationProblem);
             }
 
-            string preprocessorDirectoryValidationProblem = HydraulicBoundaryDatabaseHelper.ValidatePreprocessorDirectory(assessmentSection.HydraulicBoundaryDatabase.EffectivePreprocessorDirectory());
+            string preprocessorDirectoryValidationProblem = HydraulicBoundaryDatabaseHelper.ValidatePreprocessorDirectory(preprocessorDirectory);
             if (!string.IsNullOrEmpty(preprocessorDirectoryValidationProblem))
             {
                 validationResults.Add(preprocessorDirectoryValidationProblem);