Microsoft has changed a feature of its Windows Genuine Advantage anti-piracy technology following a public outcry.

Since its latest update on 24 April, the tool has started issuing regular warnings to users of non-genuine Windows copies and periodically contacting a Microsoft server.
The check-in is similar to that shown by spyware, according to Lauren Weinstein, co-founder of People For Internet Responsibility and the Electronic Entertainment Policy Initiative.

The checks persisted even on systems that had already cleared the anti-piracy validation as well as on systems that had the Windows Update feature disabled.

Customers are required to pass the Windows Genuine Advantage test before they are allowed to use Windows Update.

"I fail to see how Microsoft has a 'need to know' for this data after a system's validity has already been established, and there may clearly be organisations with security concerns regarding the communication of boot-time information," Weinstein wrote on his blog.

Microsoft acknowledged that the tool contacts the company after a users boot up their systems. It checks whether a new version has been released, and could receive instructions to disable itself.

"This operation is limited to the download of the new settings file. No additional information is sent to Microsoft," a spokesman told vnunet.com.

In response to the criticism the company has promised to change the check-in feature to contact the company only every 14 days.

Windows Genuine Advantage was launched in July 2005 and began as an optional feature. Microsoft has promised that security updates will be made available to all users.