Situation You are using a XmlSerializer. Problem The constructor XmlSerializer(Type) throws a FileNotFoundException when debugging. Solution Pre-Compile the Serializer. See http://msdn.microsoft.com/en-us/library/ee704594.aspx for details. Alternative Configure Visual Studio not to break on System.IO.FileNotFoundException thrown by the CLR through opening the dialog [Debug] – [Exceptions] and unchecking the checkbox for “Common Language Runtime Exceptions” – “System.IO” – “System.IO.FileNotFoundException” Sources…