Windows 10 has raised privacy concerns over its default settings, which share speech, calendar and contact information with Microsoft. Now it has emerged that even if the user chooses not to share anything with Microsoft at all, the system will still regularly contact Redmond.

According to ArsTechnica, Windows 10 pings Microsoft during certain tasks without explaining why or even giving any indication that contact is taking place, with the news site having to use specialist tools to make the discovery.

Windows 10 regularly contacts, a server apparently used for Microsoft services such as OneDrive cloud storage. During testing, contact was still made even when the system was logged in on an account not connected to Microsoft with OneDrive disabled. Other data was harder to identify, but when the system was configured to use a proxy for traffic, Windows 10 still seemingly bypassed the proxy to send requests to a content delivery network.

The system also seems to request Cortana files when a user starts typing in the Start menu, even if Cortana -- Microsoft's virtual personal assistant -- is switched off entirely and Start menu web searches are disabled. Worryingly, this request includes a random machine ID persistent across reboots, which means multiple requests could be identified as coming from one machine.

Privacy is a growing problem for end users, as customers become more concerned with how their data is being used and what they can do to control it. Ello, the social network competitor to Facebook, has capitalized on this by issuing a social networking “bill of rights” that it says every user should be entitled to. It includes giving users the ability to turn off data tracking and full control over posted content. Apple has also committed itself to user privacy by focusing on restricting third party app data access in iOS 9.

In a statement responding to the concerns, Microsoft said: “As part of delivering Windows 10 as a service, updates may be delivered to provide ongoing new features to Bing search, such as new visual layouts, styles and search code. No query or search usage data is sent to Microsoft, in accordance with the customer's chosen privacy settings. This also applies to searching offline for items such as apps, files and settings on the device.”