Britain's High Court ruled that copying CDs and DVDs you've bought to put onto your MP3 player, your computer or other devices is illegal, essentially overturning a law introduced last year that allowed you to transfer music into your home library.
The new ruling means consumers can't technically copy a CD they own and use one version in the car and another at home.
The law brought in last October made it legal to make back-ups for personal use but it always remained an offence to share those copies with friends or family or to sell on that music or data.
The judge ruled that the government was wrong legally when it decided not to introduce a compensation scheme for songwriters, musicians and other rights holders who face losses as a result of their copyright being infringed.