Microsoft has won a landmark court case against the US government concerning emails stored in a Dublin server.
Redmond won on appeal, with the court saying the company "had the better argument," rather than relying on a 30-year-old law that has become outdated.
The US Stored Communications Act "does not authorise courts to issue and enforce against U.S.based service providers warrants for the seizure of customer email content that is stored exclusively on foreign servers," a letter from Circuit Court Judge Sarah Carney said to the US Court of Appeals for the Second Circuit in New York.
A search warrant granted by the District Court for the Southern District of New York in 2013 required Microsoft to hand over emails stored on servers in Ireland sent by an unnamed person involved in the drug trafficking case.
Microsoft sent non-content information held on its US servers but refused to pass over information stored on its Ireland servers, saying US courts are not authorised to issue warrants for data held in foreign countries.
Tech companies also feared that if Microsoft was required to hand over the emails, it would mean other companies would find it a lot harder to sell applications and servers abroad if their customers thought the data was not safe from the authorities.
"This is a common sense ruling overriding the lower court's mistaken judgement that the USA court system had supremacy over all other countries sovereignty and judicial systems," Jamie Moles, principal security consultant at Lastline, said.
"The effect internationally had this ruling been upheld would have been a massive chilling of relations with American businesses across the globe and the American Judiciary would have been lining itself up for a significant fight with the European Union over data privacy laws.
"Additionally, it would likely have meant significant corporate restructuring as American owned businesses would have rushed to change their corporate structures so that their European subsidiaries ownership was moved to non-USA parentage."
