At the top of many people's privacy concerns is what data is being gathered about them as they browse the Web. That information creates a profile of a person's interests that is used by a variety of companies to target ads (resulting in the current popularity of ad blockers). Windows 10 does this with the use of an advertising ID. The ID doesn't just gather information about you when you browse the Web, but also when you use Windows 10 apps.
You can turn that advertising ID off if you want. Launch the Windows 10 Settings app (by clicking on the Start button at the lower left corner of your screen) and go to Privacy > General. There you'll see a list of choices under the title "Change privacy options;" the first controls the advertising ID. Move the slider from On to Off. You'll still get ads delivered to you, but they'll be generic ones rather than targeted ones, and your interests won't be tracked.
To make absolutely sure you're not tracked online when you use Windows 10, head to choice.microsoft.com/en-us/opt-out. In the "Personalized ads in this browser" and "Personalized ads wherever I use my Microsoft account" boxes (on the right side of the page), move the sliders from On to Off. Note that you need to go to every browser you use and make sure the slider for "Personalized ads in this browser" is set to "Off."
Wherever you go, Windows 10 knows you're there. Some people don't mind this, because it helps the operating system give you relevant information, such as your local weather, what restaurants are nearby and so on. But if you don't want Windows 10 to track your location, you can tell it to stop.
Launch the Settings app and go to Privacy > Location. Click Change and, on the screen that appears, move the slider from On to Off. Doing that turns off all location tracking for every user on the PC.
You can turn it off on a user-by-user basis as well -- so if you have several people with different accounts using the same device, they can each turn location tracking on or off. To turn location tracking on or off for any single account, sign into the account, head back to this same screen and, instead of clicking Change, go to the slider beneath the word "Location" and move it to On or Off.
Finally, this doesn't have to be all or nothing affair -- you can turn off location tracking on an app-by-app basis. If you want your location to be used only for some apps and not others, make sure location tracking is turned on, then scroll down to the "Choose apps that can use your location" section. You'll see a list of every app that can use your location. Move the slider to On for the apps you want to allow to use your location -- for example, Weather or News -- and to Off for the apps you don't.
When you turn off location tracking, Windows 10 will still keep a record of your past location history. To clear your location history, scroll to "Location History" and click Clear. Even if you use location tracking, you might want to clear your history regularly; there's no automated way to have it cleared.
Cortana is a very useful digital assistant, but there's a trade-off in using it: To do the job well, it needs to know things about you. You have a number of options for how to handle that, from turning it off completely, to only stopping some of its information-gathering.
Let's start with the simplest: Turning it off. Click in the Cortana search box on the lower left of the screen; then from the menu that appears, click the notebook icon (it's the third from the top) and click Settings. To turn Cortana off, move the top slider from On to Off.
That will stop Cortana from gathering information about you in the future, but what it already knows will still be stored in the cloud. To delete that information, click in the Cortana search box on the lower left of the screen and from the menu that appears, click the notebook icon, click Settings and then click "Manage what Cortana knows about me in the cloud."
You'll be asked to sign into your Microsoft account. Then you can clear the personal information Cortana and other Microsoft services such as Bing Maps has gathered about you under several categories: Interests (for example, Finances, News or Sports); Saved places; Search history; and Other Microsoft services.
For instance, you can delete all the information about your interests by going to the Interests section and clicking Clear. If you want to delete only information about some of your interests, first click "Interest manager" in the Interests section. In the page that appears, click the Edit button next to a type of interest (such as News or Sports). You'll then be able to delete specific interests (such as about your hometown baseball team) or add any that you do want Cortana to track.
If you want to leave Cortana on but manage what information it gathers about you, you can do that as well -- to a certain extent. Click in the Cortana search box on the lower left of the screen, then from the menu that appears click the notebook icon and then Settings. You can now turn off information gathering in several areas, such as the searches you do via Cortana on your PC and the Web, or the flight information from your emails.
One of Windows 10's most misunderstood features is Wi-Fi Sense. It's designed to let people easily share Wi-Fi connections, but some people believe it will allow friends of friends to log onto your network, and possibly do nefarious deeds.
That's not really the case. What it does do is let you share your network's bandwidth with specific people, while making sure they can't run rampant through your entire network. The feature can also automatically connect you to Wi-Fi networks that your friends share with you. For more details about how it works, you can check out this FAQ from Microsoft.
If you're still worried about Wi-Fi Sense, you can turn it off. Launch the Settings app and go to Network & Internet > Wi-Fi > Manage Wi-Fi Settings. Here you'll find all the settings that control whether and how Wi-Fi Sense should be used.
To stop connecting to networks shared with you by friends, turn the sliders from On to Off for "Connect to suggested open hotspots" and "Connect to networks shared by my contacts." To stop sharing the Wi-Fi networks you log into, go to the section titled "For networks I select, share them with my" and then uncheck Outlook.com contacts, Skype contacts and Facebook friends.
All this shouldn't take you more than five or ten minutes and will do a great deal to protect your privacy. However, if you want to dig even deeper into privacy protections, there's something else you can do.
Launch the Settings app and click Privacy. On the left-hand side of the screen, you'll see the various areas where you can get even more granular about privacy -- for example, you can click "Account info" to stop apps from accessing your name, picture and other account information; or click "Call history" to stop apps from accessing your call history from Skype.
These steps can take you a long way towards making sure that Windows 10 doesn't cross the line into gathering data you'd prefer remain private.