Index: Ringtoets/Common/src/Ringtoets.Common.Forms/Controls/FailureMechanismAssemblyResultControl.cs
===================================================================
diff -u -r718d74086633d91a350d60a463715d3bd360468b -r0822c023c37f6ed72f2ea42978c472c439e4a540
--- Ringtoets/Common/src/Ringtoets.Common.Forms/Controls/FailureMechanismAssemblyResultControl.cs	(.../FailureMechanismAssemblyResultControl.cs)	(revision 718d74086633d91a350d60a463715d3bd360468b)
+++ Ringtoets/Common/src/Ringtoets.Common.Forms/Controls/FailureMechanismAssemblyResultControl.cs	(.../FailureMechanismAssemblyResultControl.cs)	(revision 0822c023c37f6ed72f2ea42978c472c439e4a540)
@@ -20,6 +20,7 @@
 // All rights reserved.
 
 using System;
+using System.Drawing;
 using System.Windows.Forms;
 using Core.Common.Util;
 using Ringtoets.AssemblyTool.Data;
@@ -49,19 +50,21 @@
         }
 
         /// <summary>
-        /// Sets the error message of the control.
+        /// Sets the error message of the control and clears its values.
         /// </summary>
         /// <param name="error">The error message to set.</param>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="error"/>
         /// is <c>null</c>.</exception>
-        public void SetError(string error)
+        public virtual void SetError(string error)
         {
             if (error == null)
             {
                 throw new ArgumentNullException(nameof(error));
             }
 
             ErrorProvider.SetError(this, error);
+            GroupLabel.Text = string.Empty;
+            GroupLabel.BackColor = Color.White;
         }
 
         /// <summary>
Index: Ringtoets/Common/src/Ringtoets.Common.Forms/Controls/FailureMechanismAssemblyResultWithProbabilityControl.cs
===================================================================
diff -u -r718d74086633d91a350d60a463715d3bd360468b -r0822c023c37f6ed72f2ea42978c472c439e4a540
--- Ringtoets/Common/src/Ringtoets.Common.Forms/Controls/FailureMechanismAssemblyResultWithProbabilityControl.cs	(.../FailureMechanismAssemblyResultWithProbabilityControl.cs)	(revision 718d74086633d91a350d60a463715d3bd360468b)
+++ Ringtoets/Common/src/Ringtoets.Common.Forms/Controls/FailureMechanismAssemblyResultWithProbabilityControl.cs	(.../FailureMechanismAssemblyResultWithProbabilityControl.cs)	(revision 0822c023c37f6ed72f2ea42978c472c439e4a540)
@@ -20,6 +20,7 @@
 // All rights reserved.
 
 using Ringtoets.AssemblyTool.Data;
+using Ringtoets.Common.Forms.Properties;
 using Ringtoets.Common.Forms.TypeConverters;
 
 namespace Ringtoets.Common.Forms.Controls
@@ -43,5 +44,11 @@
 
             probabilityLabel.Text = new NoProbabilityValueDoubleConverter().ConvertToString(assembly.Probability);
         }
+
+        public override void SetError(string error)
+        {
+            base.SetError(error);
+            probabilityLabel.Text = Resources.RoundedDouble_No_result_dash;
+        }
     }
 }
\ No newline at end of file
Index: Ringtoets/Common/test/Ringtoets.Common.Forms.Test/Controls/FailureMechanismAssemblyResultControlTest.cs
===================================================================
diff -u -r718d74086633d91a350d60a463715d3bd360468b -r0822c023c37f6ed72f2ea42978c472c439e4a540
--- Ringtoets/Common/test/Ringtoets.Common.Forms.Test/Controls/FailureMechanismAssemblyResultControlTest.cs	(.../FailureMechanismAssemblyResultControlTest.cs)	(revision 718d74086633d91a350d60a463715d3bd360468b)
+++ Ringtoets/Common/test/Ringtoets.Common.Forms.Test/Controls/FailureMechanismAssemblyResultControlTest.cs	(.../FailureMechanismAssemblyResultControlTest.cs)	(revision 0822c023c37f6ed72f2ea42978c472c439e4a540)
@@ -81,7 +81,7 @@
         }
 
         [Test]
-        public void SetAssemblyResult_WithAssembly_SetsValuesOnControl()
+        public void SetAssemblyResult_WithAssembly_SetsValues()
         {
             // Setup
             var random = new Random(39);
@@ -128,10 +128,14 @@
             // Assert
             ErrorProvider errorProvider = GetErrorProvider(resultControl);
             Assert.AreEqual(error, errorProvider.GetError(resultControl));
+
+            Control groupLabel = GetGroupPanel(resultControl).GetControlFromPosition(1, 0);
+            Assert.AreEqual(string.Empty, groupLabel.Text);
+            Assert.AreEqual(Color.White, groupLabel.BackColor);
         }
 
         [Test]
-        public void ClearError_ClearsErrorOnControl()
+        public void ClearError_Always_ClearsErrorOnControl()
         {
             // Setup
             var resultControl = new FailureMechanismAssemblyResultControl();
Index: Ringtoets/Common/test/Ringtoets.Common.Forms.Test/Controls/FailureMechanismAssemblyResultWithProbabilityControlTest.cs
===================================================================
diff -u -r718d74086633d91a350d60a463715d3bd360468b -r0822c023c37f6ed72f2ea42978c472c439e4a540
--- Ringtoets/Common/test/Ringtoets.Common.Forms.Test/Controls/FailureMechanismAssemblyResultWithProbabilityControlTest.cs	(.../FailureMechanismAssemblyResultWithProbabilityControlTest.cs)	(revision 718d74086633d91a350d60a463715d3bd360468b)
+++ Ringtoets/Common/test/Ringtoets.Common.Forms.Test/Controls/FailureMechanismAssemblyResultWithProbabilityControlTest.cs	(.../FailureMechanismAssemblyResultWithProbabilityControlTest.cs)	(revision 0822c023c37f6ed72f2ea42978c472c439e4a540)
@@ -115,6 +115,41 @@
                             probabilityLabel.Text);
         }
 
+        [Test]
+        public void SetError_ErrorNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var resultControl = new FailureMechanismAssemblyResultControl();
+
+            // Call
+            TestDelegate test = () => resultControl.SetError(null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(test);
+            Assert.AreEqual("error", exception.ParamName);
+        }
+
+        [Test]
+        public void SetError_WithError_SetsErrorOnControl()
+        {
+            // Setup
+            const string error = "random error 123";
+            var resultControl = new FailureMechanismAssemblyResultWithProbabilityControl();
+
+            // Call
+            resultControl.SetError(error);
+
+            // Assert
+            var errorProvider = TypeUtils.GetField<ErrorProvider>(resultControl, "ErrorProvider");
+            Assert.AreEqual(error, errorProvider.GetError(resultControl));
+
+            Control groupLabel = GetGroupPanel(resultControl).GetControlFromPosition(1, 0);
+            Control probabilityLabel = GetProbabilityPanel(resultControl).GetControlFromPosition(0, 0);
+            Assert.AreEqual(string.Empty, groupLabel.Text);
+            Assert.AreEqual(Color.White, groupLabel.BackColor);
+            Assert.AreEqual("-", probabilityLabel.Text);
+        }
+
         private static TableLayoutPanel GetProbabilityPanel(FailureMechanismAssemblyResultWithProbabilityControl resultControl)
         {
             return TypeUtils.GetField<TableLayoutPanel>(resultControl, "probabilityPanel");