Redmond (WA) - Microsoft officially put an end to its PlaysForSure digital rights management last year, but said it would continue to support the platform for users with existing MSN Music tracks.

However, the software giant is now going to stop all support of the defunct DRM. After August 31, all PlaysForSure music that people bought will essentially be locked.

Microsoft announced this week that it will no longer offer authorization keys for tracks bought on MSN Music. In other words, music that users bought on MSN Music will be tied to the computers and devices on which they currently exist but will become immobile to other devices.

"If you attempt to transfer your songs to additional computers after August 31, 2008, those songs will not successfully play," said Microsoft in an e-mail.

It is similar to Sony’s move to kill off its "Atrac" format and related Connect music store. Sony began a new digital audio strategy, as its current line of music players support Windows Media, MP3 and AAC files, but not Atrac. Users are still able to transfer Atrac files to and from existing compatible players, but they aren’t be compatible with new Walkman devices. Users also can’t transfer purchased music to new computers.

Additionally, like Sony, Microsoft suggests that users burn their existing MSN Music tracks to CDs and then rip them back to their computer to get rid of the DRM.