Song swapping portal Napster must remove all offending material from its site by Wednesday or face closure and contempt of court charges.
Leading record companies delivered a list of around 135,000 offending songs at the weekend, giving Napster three days to block users accessing these songs.
Napster said its team was working “flat out” and were confident they would have the filter in place by Wednesday.
In a last-ditch attempt to reach some sort of compromise lawyers, Napster and the Recording Industry Association of America met up on Friday. Neither side would comment on the meeting.
But hackers are challenging the company's fragile future. Many are using services such as Napstercameback.com, which enables users to input a scrambled version of song titles that escape Napster’s monitoring.
Napster said it is still pressing for a subscription-based service.
The struggling company hopes hackers do not prevent it from complying with the US appeals courts decision that it must police itself. Wednesday is judgement day.