A software patch released by Sony following an uproar over its XCP CD copy protection software may cause some computers to crash.

According to the computer expert at the heart of the controversy, Winternals chief software architect Mark Russinovich, the patch raises new privacy concerns about the product.

Russinovich has published further research into Sony's software, claiming that a design flaw could cause a computer to crash as the software was installed. Though the risk is small, Russinovich said that the problem was a further mark against Sony's reputation. "It's obvious that whoever's written this doesn't have all that much experience in writing drivers for Windows," he said.

Sony released the patch on Wednesday in response to complaints from computer enthusiasts that XCP (Extended Copy Protection) used methods commonly associated with spyware and viruses to make itself nearly impossible to detect or remove from a PC. If the software were to slow down a computer's performance or somehow be exploited by hackers, it could be extremely difficult to repair, according to critics including Russinovich.

Sony licenses XCP from a Banbury company called First 4 Internet and began shipping the software with some of its CDs earlier this year, in order to restrict unauthorised copying. Sony executives have said that only about 20 music titles have shipped with the software.

On his blog, Russinovich has published further research showing that the XCP software appears to be in communication with Sony's website - something that had not previously been disclosed.

The client connects with Sony's servers looking for updates to lyrics or album art, but the way the software operates raises some privacy concerns, Russinovich said. "I doubt Sony is doing anything with the data, but with this type of connection their servers could record each time a copy-protected CD is played and the IP address of the computer playing it."

Sony is not using the software to gather information on its users, a company spokesman promised. "No information ever gets gathered, that's for sure," he said.