A federal appeals court on Thursday said Microsoft and other companies cannot be forced to turn over customer emails stored on servers outside the United States, handing a victory to privacy advocates.
The 2nd U.S. Circuit Court of Appeals in New York reversed a 2014 lower court order directing Microsoft to comply with a warrant to turn over to the U.S. government the contents of a customer’s email account stored on an Irish server. It also voided a finding of contempt against Microsoft.
Circuit Judge Susan Carney said warrants issued under the federal Stored Communications Act reach only data stored within the United States, and that U.S. service providers cannot be forced to comply with warrants seeking data stored elsewhere.
Microsoft (msft) had been the first U.S. company challenging a warrant seeking data held outside the country.
It had warned that enforcing its warrant could spark a “global free-for-all” that eviscerated personal privacy, and prompt law enforcement authorities elsewhere to seize emails belonging to Americans and stored in the United States.
Get Data Sheet, Fortune’s technology newsletter.
The case has attracted strong interest from the technology and media sectors. Nearly 100 companies, organizations, and individuals had filed briefs supporting Microsoft, including Apple (aapl), Cisco Systems (csco), Gannett (gci), and Verizon Communications (vz).
The warrant in question had sought emails stored on a server in Dublin in connection with a narcotics case.