Microsoft is giving users of its now-defunct MSN Music service three years to move music files purchased to new devices.

Tracks purchased on the US-only service used Microsoft's 'PlaysForSure' digital right management (DRM) that needed a licence key from a Microsoft server if a user wanted to transfer it to a new PC or digital audio device.

Initially Microsoft said that it would support authenticating songs from MSN Music, which was shut down in November 2006, only until Aug 31 2008. The decision meant that users could no longer migrate their music to a new PC if they upgraded their hardware.

If a PC died, the music would be gone unless it had been backed up on a CD or to another hard drive. Even if a user merely upgraded their operating system, for example from Windows XP to Vista, authentication is still required.

Microsoft's decision drew fire from users and organisations such as the Electronic Frontier Foundation, which said consumers should be entitled to refunds. However, Microsoft has now said it will support tracks until at least the end of 2011.

MSN Music, one of several online music store efforts by Microsoft, was shut down when the company launched the Zune Marketplace, which is centered around its Zune digital music player. Some content is available in unprotected MP3 format as the music industry warms to the idea of selling music without DRM after backlash from consumers.

Apple, whose iTunes Music Store remains the most popular place to buy music online, is selling some tracks minus its version of DRM, called FairPlay, after new agreements were reached with music labels. Amazon also sells songs from Warner Music Group without DRM in the MP3 format.

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