diff --git a/dg.Sql/Sql/Query/Query.cs b/dg.Sql/Sql/Query/Query.cs
index 238ea0c5..eaba2416 100644
--- a/dg.Sql/Sql/Query/Query.cs
+++ b/dg.Sql/Sql/Query/Query.cs
@@ -386,8 +386,11 @@ public static void PrepareColumnValue(TableSchema.Column columnDefinition, objec
                     }
                     else if (columnDefinition.Type == typeof(Guid))
                     {
-                        Guid gValue = new Guid((string)value);
-                        value = gValue;
+                        Guid gValue;
+                        if (Guid.TryParse((string)value, out gValue))
+                        {
+                            value = gValue;
+                        }
                     }
                 }
                 else