diff --git a/src/Core/WinSWCore/Util/XmlHelper.cs b/src/Core/WinSWCore/Util/XmlHelper.cs
index 5e79db1..f28a2f0 100644
--- a/src/Core/WinSWCore/Util/XmlHelper.cs
+++ b/src/Core/WinSWCore/Util/XmlHelper.cs
@@ -55,7 +55,7 @@ namespace winsw.Util
                 throw new InvalidDataException("Attribute <" + attributeName + "> is missing in configuration XML");
             }
 
-            return SingleAttribute<TAttributeType>(node, attributeName, default);
+            return SingleAttribute<TAttributeType>(node, attributeName, default)!;
         }
 
         /// <summary>