Index: Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/Views/GrassCoverErosionOutwardsFailureMechanismSectionResultRow.cs
===================================================================
diff -u -ra6ebd668680c82a4b7822d979c7be3c3ad11ff7b -re1f407b3d93adfa477726ede6ba785c3a7eac991
--- Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/Views/GrassCoverErosionOutwardsFailureMechanismSectionResultRow.cs	(.../GrassCoverErosionOutwardsFailureMechanismSectionResultRow.cs)	(revision a6ebd668680c82a4b7822d979c7be3c3ad11ff7b)
+++ Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/Views/GrassCoverErosionOutwardsFailureMechanismSectionResultRow.cs	(.../GrassCoverErosionOutwardsFailureMechanismSectionResultRow.cs)	(revision e1f407b3d93adfa477726ede6ba785c3a7eac991)
@@ -335,12 +335,21 @@
 
         private void UpdateDerivedData()
         {
+            ResetErrorTexts();
             TryGetSimpleAssemblyCategoryGroup();
             TryGetDetailedAssemblyCategoryGroup();
             TryGetTailorMadeAssemblyCategoryGroup();
             TryGetCombinedAssemblyCategoryGroup();
         }
 
+        private void ResetErrorTexts()
+        {
+            ColumnStateDefinitions[simpleAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+            ColumnStateDefinitions[detailedAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+            ColumnStateDefinitions[tailorMadeAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+            ColumnStateDefinitions[combinedAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+        }
+
         private void TryGetSimpleAssemblyCategoryGroup()
         {
             try
@@ -350,6 +359,7 @@
             catch (AssemblyException e)
             {
                 simpleAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[simpleAssemblyCategoryGroupIndex].ErrorText = e.InnerException.Message;
             }
         }
 
@@ -362,6 +372,7 @@
             catch (AssemblyException e)
             {
                 detailedAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[detailedAssemblyCategoryGroupIndex].ErrorText = e.InnerException.Message;
             }
         }
 
@@ -374,6 +385,7 @@
             catch (AssemblyException e)
             {
                 tailorMadeAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[tailorMadeAssemblyCategoryGroupIndex].ErrorText = e.InnerException.Message;
             }
         }
 
@@ -387,6 +399,7 @@
             catch (AssemblyException e)
             {
                 combinedAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[combinedAssemblyCategoryGroupIndex].ErrorText = e.InnerException.Message;
             }
         }