Kazaa users were warned of potential copyright infringement issues before they used the system, a witness for the record companies conceded on Tuesday.
Professor Leon Sterling, Adacel chair of software innovation and engineering, University of Melbourne, had told the Federal Court in affidavits that Kazaa did not adequately warn users of the potential for copyright infringement.
However, questioned for over an hour by Sharman lawyers, he conceded the warning was clear in two pages in the Kazaa user guide.
Junior counsel for Altnet, Mark Leeming, said the Kazaa user guide asked users several times to "take great care" in choosing files to upload.
The guide said Kazaa was "a great tool to promote your own... content", and was not encouraging piracy, according to Leeming.
He asked Sterling to clarify the affidavit claim that Kazaa users were encouraged to place any files they owned in the "My Shared Folder".
Sterling said he agreed the point was clear in the pages cited by Leeming, but was "not sure that [message] is universally present in the system".
Leeming also attacked Sterling's proposal to filter Kazaa by installing a list of copyright-owned songs in the system.
The Napster case in the US had heard that any list of songs installed in a filter to block unauthorised file sharing would have to number around eight million, according to Leeming.
"That's a lot of metadata," he said.
Sterling's claim that Kazaa could maintain a list of user names was unsubstantiated, according to Leeming.
"Aren't you saying here that Kazaa should be a centralised system?" Leeming said.
Sterling said supernodes, used in the Kazaa system, could maintain such a list as "they're quite stable."
However, Leeming said a study of the system by Professor Keith Ross, chair in computer science at Polytechnic University in New York found the average life of Kazaa supernodes to be less than two and a half hours.
Sharman is expected to continue questioning Sterling when the trial resumes tomorrow.
Court had been adjourned earlier on Tuesday till the afternoon, as Sterling had filed a new affidavit. Sharman had asked the judge for more time so its lawyers could read over the document.