European Union data protection watchdogs, Article 29 Working Party, have said they still have concerns about the privacy settings of Microsoft's Windows 10 operating system, despite the US company announcing changes to the installation process.

The watchdog, which enforces data protection law, wrote to Microsoft last year expressing concerns about the default installation settings of Windows 10 and users' apparent lack of control over the company's processing of their data.

Despite a new installation screen presenting users with five options to limit or switch off Microsoft's processing of their data, the Working Party was not clear to what extent users would be informed about the specific data being collected.

Windows 10 had come under fire in 2015 thanks to its data collection processes, to which  Microsoft executive vice president Terry Myerson responded by posting a clarifying statement on the company blog, and emphasised that the information the company collects is encrypted and doesn't include personal identifiers, content or files.

Microsoft views data that it does and doesn't collect at three levels, “safety and reliability data”, “personalisation data” and “advertising data we don't collect,” Myerson said in the blog.

The “safety and reliability data” has already been used to fix a bug that caused some PCs to crash and reboot, according to the post. Myerson said personalisation data is used for recommending apps, text completion suggestions, and other things the user may like.

What is not done, Myerson said, is scan emails or personal messages to deliver targeting advertising.

The group asked for more explanation of Microsoft's processing of personal data for various purposes, including advertising, "the Working Party remains concerned about the level of protection of users' personal data," the group said in a statement.

The comment from the Working Party follows a request by the French minister who in July 2016 ordered Microsoft to stop collecting “excessive” user data.

Microsoft uses data collected through Windows 10 for different purposes, including advertising, the group said in its statement said, "Microsoft should clearly explain what kinds of personal data are processed for what purposes. Without such information, consent cannot be informed, and therefore, not valid."