A judge in the US overseeing the case against Napster has appealed for help in stopping the exchange of copyright songs.
For the moment Judge Marilyn Hall Patel's ruling guarantees Napster users can continue downloading copyright music at will.
Major record labels want the online music-swapping service to remove any copyright songs from its internet site.
Removing the songs is proving difficult, since Napster users constantly make them reappear under different file names. Napster has said it cannot keep up with every variation.
The District Judge says that unless an appeals court clarifies its ruling in the case, she cannot force Napster to identify and remove all those files.
It will therefore be up to record labels to identify infringing songs.
She has invited the Recording Industry Association of America to "seek clarification in the court of appeals".
The 9th US Circuit Court of Appeals upheld Judge Patel's order that Napster remove all copyrighted works from its file-swapping site.
However, the appeals court said the RIAA must "provide notice to Napster of copyrighted works and files containing such works available on the Napster system before Napster has the duty to disable access to the offending content".
Napster says it has to screen out songs only after the RIAA identifies the specific infringing files, along with proof of copyright. For example, many Beatles songs come under the name Fab Four. Napster says that unless the record labels can prove that they are Beatles songs, it is not obligated to remove them.