diff --git a/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Eventing/ExceptionsEventSource.cs b/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Eventing/ExceptionsEventSource.cs
index efa325bb9a9..95806453b32 100644
--- a/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Eventing/ExceptionsEventSource.cs
+++ b/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Eventing/ExceptionsEventSource.cs
@@ -35,11 +35,11 @@ public void ExceptionGroup(
         public void ExceptionInstance(
             ulong ExceptionId,
             ulong ExceptionGroupId,
-            string? ExceptionMessage,
+            string ExceptionMessage,
             ulong[] StackFrameIds,
             DateTime Timestamp,
             ulong[] InnerExceptionIds,
-            string? ActivityId,
+            string ActivityId,
             ActivityIdFormat ActivityIdFormat)
         {
             Span<EventData> data = stackalloc EventData[8];
diff --git a/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Pipeline/Steps/ExceptionEventsPipelineStep.cs b/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Pipeline/Steps/ExceptionEventsPipelineStep.cs
index ec3dd331d44..6d8455208e7 100644
--- a/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Pipeline/Steps/ExceptionEventsPipelineStep.cs
+++ b/src/Microsoft.Diagnostics.Monitoring.StartupHook/Exceptions/Pipeline/Steps/ExceptionEventsPipelineStep.cs
@@ -60,7 +60,7 @@ public void Invoke(Exception exception, ExceptionPipelineExceptionContext contex
                     frameIds,
                     context.Timestamp,
                     GetInnerExceptionsIds(exception),
-                    context.ActivityId,
+                    context.ActivityId ?? string.Empty,
                     context.ActivityIdFormat
                     );
             }
diff --git a/src/Microsoft.Diagnostics.Monitoring.WebApi/Exceptions/IExceptionInstance.cs b/src/Microsoft.Diagnostics.Monitoring.WebApi/Exceptions/IExceptionInstance.cs
index 5b178bc477a..9ab5869d3d4 100644
--- a/src/Microsoft.Diagnostics.Monitoring.WebApi/Exceptions/IExceptionInstance.cs
+++ b/src/Microsoft.Diagnostics.Monitoring.WebApi/Exceptions/IExceptionInstance.cs
@@ -23,7 +23,7 @@ internal interface IExceptionInstance
 
         ulong[] InnerExceptionIds { get; }
 
-        public string? ActivityId { get; }
+        public string ActivityId { get; }
 
         public ActivityIdFormat ActivityIdFormat { get; }
     }
diff --git a/src/Tests/Microsoft.Diagnostics.Monitoring.StartupHook.UnitTests/Exceptions/Eventing/ExceptionsEventSourceTests.cs b/src/Tests/Microsoft.Diagnostics.Monitoring.StartupHook.UnitTests/Exceptions/Eventing/ExceptionsEventSourceTests.cs
index 64b9ba75129..2fbf7109167 100644
--- a/src/Tests/Microsoft.Diagnostics.Monitoring.StartupHook.UnitTests/Exceptions/Eventing/ExceptionsEventSourceTests.cs
+++ b/src/Tests/Microsoft.Diagnostics.Monitoring.StartupHook.UnitTests/Exceptions/Eventing/ExceptionsEventSourceTests.cs
@@ -108,7 +108,7 @@ public void ExceptionsEventSource_WriteException_LevelTooHigh()
             using ExceptionsEventListener listener = new();
             listener.EnableEvents(source, EventLevel.Warning);
 
-            source.ExceptionInstance(5, 7, ObjectDisposedExceptionMessage, Array.Empty<ulong>(), DateTime.UtcNow, Array.Empty<ulong>(), null, ActivityIdFormat.Unknown);
+            source.ExceptionInstance(5, 7, ObjectDisposedExceptionMessage, Array.Empty<ulong>(), DateTime.UtcNow, Array.Empty<ulong>(), string.Empty, ActivityIdFormat.Unknown);
 
             Assert.Empty(listener.Exceptions);
         }
@@ -120,7 +120,7 @@ public void ExceptionsEventSource_WriteException_NotEnabled()
 
             using ExceptionsEventListener listener = new();
 
-            source.ExceptionInstance(7, 9, OperationCancelledExceptionMessage, Array.Empty<ulong>(), DateTime.UtcNow, Array.Empty<ulong>(), null, ActivityIdFormat.Unknown);
+            source.ExceptionInstance(7, 9, OperationCancelledExceptionMessage, Array.Empty<ulong>(), DateTime.UtcNow, Array.Empty<ulong>(), string.Empty, ActivityIdFormat.Unknown);
 
             Assert.Empty(listener.Exceptions);
         }