Privacy-conscious Windows 10 users have been warned that a number of features transmit data to Microsoft servers even when they have been turned off and privacy systems are activated.
An analysis published by Ars Technica said that some features that rely on an internet connection, including Cortana and Bing, continue to send "random machine data" to Microsoft that persists across reboots.
The research found that, even when Cortana or searching the web from the Start menu is disabled, the features continue to send requests to Bing.com for a file called threshold.appcache that appears to hold Cortana information.
Most of the data is deemed harmless, but in one case the research showed that the OneDrive cloud service periodically sends telemetry data to a server while switched off, even when log-in is from a local account that isn't connected to a Microsoft account. In any case, the requests are "very bare, with no machine IDs or other data sent".
However, the report said that, in a number of cases, it is unclear why data is being sent at all.
"Even with no Live tiles pinned to Start (and hence no obvious need to poll for new tile data), Windows 10 seems to download new tile info from MSN's network from time to time, using unencrypted HTTP to do so," the report said.
"While again the requests contain no identifying information, it's not clear why they're occurring at all, given that they have no corresponding tile."
A Microsoft spokesperson told V3 in response that no query or search 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. 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," the spokesperson said.
The report comes after numerous privacy concerns were raised following the launch of the operating system last month, ranging from WiFi password sharing to the sort of data Microsoft gathers and how it is shared.
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