The FBI issued a National Security Letter to Microsoft in 2013, which requested subscriber information about a single user account for one of the company’s enterprise customers. Microsoft concluded the request “was unlawful and violated our Constitutional right to free expression” But the FBI withdrew its letter after Microsoft filed a petition challenging the request. The FBI obtained the information it sought directly from the Microsoft customer it had targeted in a way that maintained “the confidentiality of the investigation” Microsoft is one of many technology companies that have vowed to closely scrutinize U.S. government requests for data.”]