A major change to US music copyright practices could be in the offing after a court ruled a record label broke the law by reissuing old recordings.
Yehudi Menuhin's music was among the contested recordings
New York's highest court said Naxos was wrong to release classical recordings by Yehudi Menuhin and others - even though they were out of copyright.
The court said such recordings were still covered by common law.
The victorious Capitol label, which owns the rights, said the decision had "enormous importance".
But Naxos said there was "a certain insanity" to the ruling and warned it would stop labels restoring and re-releasing lost recordings.
Naxos restored and reissued sessions made in the UK for The Gramaphone Co in the 1930s by Menuhin, Edwin Fisher and Pablo Casals.
UK law only protects recordings for 50 years and they were not covered by a US federal copyright law that came into force in 1972.
But on Tuesday, the New York Court of Appeals said the rights owned by Capitol, a descendant of The Gramaphone Co, were protected under common law.
The decision could have an impact on pop and rock music as the copyright on recordings made by British stars such as The Beatles and Sir Cliff Richard start to reach their 50-year time limits soon.
Philip Allen Lacovara, lawyer for Capitol Records, part of EMI, said the ruling meant the artists and their estates could collect royalties for the sales.
"I hope the companies who have been inclined to copy older classical recordings realise the New York court has spoken definitively on this and end any unlicensed copying," he said.
Naxos describes itself as "the world's leading classical music label" and in 1997 launched its Naxos Historical division to specialise in remastering and cheaply selling out-of-copyright recordings.