diff --git a/Implab/Diagnostics/TraceEvent.cs b/Implab/Diagnostics/TraceEvent.cs
--- a/Implab/Diagnostics/TraceEvent.cs
+++ b/Implab/Diagnostics/TraceEvent.cs
@@ -41,7 +41,7 @@ namespace Implab.Diagnostics {
         }
 
         public static TraceEvent Create(LogicalOperation operation, TraceEventType type, string format, params object[] args) {
-            return new TraceEvent(operation, type, format == null ? String.Empty : String.Format(format, args));
+            return new TraceEvent(operation, type, format == null ? String.Empty : args == null || args.Length == 0 ? format : String.Format(format, args));
         }
     }
 }