Note Sequence editors you create with TestStand assign new unique IDs to steps that you duplicate in the editor. However, the value of Step.UniqueStepId is not unique if you duplicate a step using the TestStand API or if you copy a sequence file using the file system. It is incorrect programming practice to create a non-unique UniqueStepId using the API. Call Step.CreateNewUniqueStepId to ensure that a programmatically duplicated step has a unique ID. At run time, you can guard against mistakenly matching steps from duplicated files by Step.UniqueStepId . To do so, append the string representation of the value of Step.Sequence.SequenceFile.Id to the Step.UniqueStepId value before comparing it.