Sony BMG's release of a software patch for a controversial anti-piracy program has failed to stem criticism.
Sony BMG's anti-piracy methods have been called heavy-handed
The patch was made available following widespread disapproval of Sony's methods of stopping illegal CD copying.
But the patch has left unimpressed the man who started the debate about Sony's copy protection policy.
Analysing the patch, Mark Russinovich said it did not do enough to allay user fears and he urged Sony to release a full uninstallation program.
In an entry posted to his SysInternals blog on 31 October Mr Russinovich wrote about his discovery of the "cloaked" files Sony BMG was using to stop people making illegal copies of a CD by country rock group Van Zant.
The files were used for a proprietary music player on Windows machines needed to play the CD. Mr Russinovich was outraged that the licence agreement for the CD made no mention of the methods used to hide the files or that the player could not be uninstalled.
The files were hidden deep inside the Windows system using techniques more often used by skilled virus writers said Mr Russinovich, a claim backed up by Finnish security firm F-Secure which performed a separate analysis on the proprietary player.
F-Secure said it feared that virus writers would use the cloaking system to hide their own creations making them impossible to find.
Already some have suggested that the cloaking system could be used to hide hacks for the popular World of Warcraft online game.
Mr Russinovich's analysis generated a huge amount of publicity and led to many calling on Sony BMG to abandon this type of copy protection software.
On the Amazon page for the Van Zant CD, more than 140 people have left comments decrying Sony's tactics.
In response Sony BMG made a patch available that revealed the "cloaked" files and stopped the proprietary media player loading.
Some have suggested using the Sony system to hide Warcraft cheats
Mr Russinovich has subjected the patch to further analysis and did not like what he found. Writing in his blog, the Windows programming expert said that the patch left intact the hidden files and used a potentially unsafe method to stop the player loading.
He added that there were still unresolved questions about whether Sony did enough to warn about what the copy protection system did to users' computers.
By installing the player and the hidden files users were unwittingly giving up control over part of the computer and leaving themselves open to a number of risks, he said.
"There's no way to ensure that you have up-to-date security patches for software you don't know you have and there's no way to remove, update or even identify hidden software that's crashing your computer," he wrote.
Sony BMG should produce proper uninstallation software and be much more explicit about the methods it was using to stop its CDs being copied, said Mr Russinovich.
Currently anyone wishing to uninstall the proprietary player must apply to Sony BMG via a website. Mr Russinovich has applied to Sony for the uninstaller and plans to post an analysis of that when it arrives.
First 4 Internet, which made the copy protection system for Sony BMG, said that it would work with anti-virus companies to ensure that false alarms were not triggered by its software.
Sony says that users have been adequately warned about the copy protection software in the licence agreement and had been told that it used proprietary software to play the CD.