A federal district court judge has told Napster to remain out of service until its filtering technology can comply with a previous ruling that restricts access to copyright material on the file-sharing service. Interim CEO Hank Barry said Napster told the court yesterday (July 11) that it had reached 99% effectiveness in screening out copyrighted works. But U.S. District Judge Marilyn Hall Patel ordered Napster not to resume operations until it can prove that the system is 100% effective.

Earlier this month, Napster voluntarily halted service to retool its filters. Although disappointed by the ruling, Barry said the service will obey the order while appealing it "to the Ninth Circuit on an expedited basis."

Yesterday's ruling is the latest blow in the year-and-a-half of legal wrangling over copyright infringement between Napster and the Recording Industry Association of America (RIAA), the trade organization that represents the five major label groups -- Sony Music, EMI, Warner Music Group, Universal Music Group, and BMG Entertainment. Napster over the past few months has been attempting to legitimize itself and keep its user base while it prepares to launch a legal pay subscription service this summer.

In March, Patel ruled that the company must take down all music files identified by the record labels as protected under copyright laws. Napster has repeatedly said that it is complying with the order by putting filtering mechanisms in place. The RIAA, however, has repeatedly provided the court with evidence that Napster continues to trade in copyrighted works.

RIAA president/CEO Hilary Rosen hailed the order as a deterrent to infringers hiding behind "the shield of technological innovation."