Record company Sony BMG Music Entertainment has been targeted in a class-action lawsuit in California by consumers claiming their computers have been harmed by anti-piracy software on some Sony BMG CDs.

The claim states that Sony BMG's failed to disclose the true nature of the digital rights management system it uses on its CDs, and thousands of computer users have unknowingly infected their computers, according to court documents.

The suit, filed November 1 in Los Angeles Superior Court, asks the court to stop Sony BMG from selling additional CDs protected by the anti-piracy software and seeks monetary damages for California consumers who purchased them.

A spokesman for Sony BMG declined comment.

Sony BMG is a joint venture of Sony Corp (SNE) and Bertelsmann AG.

Alan Himmelfarb, the attorney for the consumers, was not available for comment.

The suit claims that around June 2005, Sony BMG began to issue some CDs that install digital rights management software that continuously monitor for rights problems, depleting a computer's available resources.

The suit says the technology cannot be removed without damage to the system and that Sony BMG does not advise consumers of the existence or true nature of the program.