diff --git a/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/MarkupExtensionSerializer.cs b/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/MarkupExtensionSerializer.cs
index 7b857f6..a11f8ac 100644
--- a/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/MarkupExtensionSerializer.cs
+++ b/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/MarkupExtensionSerializer.cs
@@ -76,7 +76,7 @@ protected internal sealed override string SerializeToString(WorkflowMarkupSerial
                                 }
                                 else
                                 {
-                                    writer.WriteString(argType.FullName);
+                                    writer.WriteString(argType?.FullName ?? string.Empty);
                                 }
                             }
                             else
diff --git a/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/WorkflowMarkupSerializer.cs b/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/WorkflowMarkupSerializer.cs
index 536d544..cc033a2 100644
--- a/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/WorkflowMarkupSerializer.cs
+++ b/LogicBuilder.Workflow.ComponentModel.Serialization/ComponentModel/Serialization/WorkflowMarkupSerializer.cs
@@ -557,7 +557,7 @@ internal void SerializeContents(WorkflowMarkupSerializationManager serialization
                 {
                     writer.WriteValue(obj);
                 }
-                // For Key properties, we don;t want to get the extended properties
+                // For Key properties, we don't want to get the extended properties
                 if (!dictionaryKey)
                     properties.AddRange(serializationManager.GetExtendedProperties(obj));
             }
@@ -586,24 +586,18 @@ internal void SerializeContents(WorkflowMarkupSerializationManager serialization
                 }
             }
 
-            if (properties != null)
+            foreach (PropertyInfo propInfo in properties)
             {
-                foreach (PropertyInfo propInfo in properties)
-                {
-                    // Do not serialize properties that have corresponding dynamic properties.
-                    if (propInfo != null && !allProperties.ContainsKey(propInfo.Name))
-                        allProperties.Add(propInfo.Name, propInfo);
-                }
+                // Do not serialize properties that have corresponding dynamic properties.
+                if (propInfo != null && !allProperties.ContainsKey(propInfo.Name))
+                    allProperties.Add(propInfo.Name, propInfo);
             }
 
-            if (events != null)
+            foreach (EventInfo eventInfo in events)
             {
-                foreach (EventInfo eventInfo in events)
-                {
-                    // Do not serialize events that have corresponding dynamic properties.
-                    if (eventInfo != null && !allProperties.ContainsKey(eventInfo.Name))
-                        allProperties.Add(eventInfo.Name, eventInfo);
-                }
+                // Do not serialize events that have corresponding dynamic properties.
+                if (eventInfo != null && !allProperties.ContainsKey(eventInfo.Name))
+                    allProperties.Add(eventInfo.Name, eventInfo);
             }
 
             using (ContentProperty contentProperty = new(serializationManager, serializer, obj))
diff --git a/Workflow.ComponentModel.Serialization.Tests/ComponentModel/Design/HelpersTest.cs b/Workflow.ComponentModel.Serialization.Tests/ComponentModel/Design/HelpersTest.cs
index 36bec69..f5b6569 100644
--- a/Workflow.ComponentModel.Serialization.Tests/ComponentModel/Design/HelpersTest.cs
+++ b/Workflow.ComponentModel.Serialization.Tests/ComponentModel/Design/HelpersTest.cs
@@ -121,6 +121,7 @@ public void CreateXmlWriter_WithInvalidType_ReturnsNull()
         public void CreateXmlWriter_WithNull_ReturnsNull()
         {
             // Arrange
+            System.Diagnostics.Trace.Listeners.Clear();
             object? nullOutput = null;
 
             // Act
diff --git a/Workflow.ComponentModel.Serialization.Tests/ComponentModel/SynchronizationHandlesTypeConverterTest.cs b/Workflow.ComponentModel.Serialization.Tests/ComponentModel/SynchronizationHandlesTypeConverterTest.cs
index d1b88f0..0e6003f 100644
--- a/Workflow.ComponentModel.Serialization.Tests/ComponentModel/SynchronizationHandlesTypeConverterTest.cs
+++ b/Workflow.ComponentModel.Serialization.Tests/ComponentModel/SynchronizationHandlesTypeConverterTest.cs
@@ -185,7 +185,7 @@ public void ConvertFrom_UnescapesCommas()
             string input = "handle\\,with\\,commas, normalHandle";
 
             // Act
-            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string>;
+            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string> ?? Array.Empty<string>();
 
             // Assert
             Assert.NotNull(result);
@@ -201,7 +201,7 @@ public void ConvertFrom_TrimsWhitespace()
             string input = "  handle1  ,  handle2  ";
 
             // Act
-            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string>;
+            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string> ?? Array.Empty<string>();
 
             // Assert
             Assert.NotNull(result);
@@ -217,7 +217,7 @@ public void ConvertFrom_HandlesNewlineDelimiters()
             string input = "handle1\r\nhandle2\nhandle3";
 
             // Act
-            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string>;
+            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string> ?? Array.Empty<string>();
 
             // Assert
             Assert.NotNull(result);
@@ -234,7 +234,7 @@ public void ConvertFrom_RemovesDuplicates()
             string input = "handle1, handle2, handle1, handle3";
 
             // Act
-            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string>;
+            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string> ?? Array.Empty<string>();
 
             // Assert
             Assert.NotNull(result);
@@ -248,7 +248,7 @@ public void ConvertFrom_SkipsEmptyEntries()
             string input = "handle1,  ,handle2,   ";
 
             // Act
-            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string>;
+            var result = _converter.ConvertFrom(null, CultureInfo.InvariantCulture, input) as ICollection<string> ?? Array.Empty<string>();
 
             // Assert
             Assert.NotNull(result);