When evaluating digital evidence, its reliability and accuracy are of great importance to our jurisprudence both in investigation and in the probative stages of any particular case. Whether digital evidence is being used to implicate or exonerate a person, how reliably and accurately the data represent actual events can impact an individual’s liberty and life. The computer system and process that generate records for whatever use can introduce more subtle errors that are only detectable through detailed analysis. In some cases, it may arise due to system malfunction. Chapter 17 examines these possible errors or malfunctions of the system that may render the record so generated un-used by the court.