Microsoft will change the number of times its Windows Genuine Advantage (WGA) anti piracy checks are made on PCs, following accusations that the current daily regime is tantamount to spying.

Since its latest update on 24 April, the tool has started issuing regular warnings to users of non-genuine Windows copies and also periodically contacting a Microsoft server.

The checks persist even on systems that have already cleared the anti-piracy validation as well as on systems that had the Windows Update feature disabled, according to civil liberties and privacy organisations People For Internet Responsibility and the Electronic Entertainment Policy Initiative.

The WGA programme is Microsoft's anti piracy measure which was launched in July 2005. It became mandatory in the UK in April this year when people were asked to verify that their copy of Windows XP was legitimate.

When a user runs WGA Validation for the first time to check if their version of Windows XP is genuine it sends certain information back to Microsoft.

This comprises the Windows XP product key, the PC manufacturer, the version of the operating system version, the PC Bios information and the user's locale setting and language.

If a user refuses to participate or a copy is pirated, they are unable to get many new features, such as Windows Defender anti spyware and other updates.

Microsoft has continued however to allow people with pirated or invalidated copies to download critical updates.

However even though a copy of XP may be validated on a PC, the WGA validation tool has continued to make checks on PCs. Microsoft said these criticised checks are necessary as it is continually updating the records of licence keys as it finds more counterfeit copies.

It said no personally identifiable system information is sent to Microsoft when these check are made.

"The settings file gives Microsoft the ability to update how often reminders are displayed and to disable the program if necessary during the test period.

"For example, if the company suddenly started seeing a rash of reports that Windows copies were pirated, it might want to shut down the program to make sure it wasn't delivering false results," the company told us.

However as a result of customer concerns around performance, Microsoft will now change the WGA Notifications feature from a daily check for a new settings file to once every 14 days.

It also said agreed it should have made the WGA reporting policy clearer to consumers.

This change will be made in the next release of WGA later this year. Microsoft also told us that this controversial feature will be disabled when WGA Notifications launches worldwide later this year.

See also: Microsoft increases checks for pirated software via Windows Genuine Advantage