A friend told me that any application I run on my new Windows 10.1 system can access my entire Contacts and address book. That’s not what I want! How can I control what apps see my friends names and addresses?
Your friend is right that any application you run on your Microsoft Windows 10 or Win10.1 system can theoretically gain access to your location, your contacts directory of friends and family and much more. However, the operating system itself is designed to make that difficult to accomplish and should pop up a request window for each type of data that an app wants to access, and you are always free to say “no” and block that particular stream.
However, my experience is that there are still some apps that somehow seem to slip through the proverbial cracks and end up with access to things you don’t want. For example, did you know that the Xbox app has access to your Contacts? Let’s have a look!
To start, you want to do a simple Cortana search for “Privacy” to get to the right settings page:

There are a lot of privacy settings and it’s quite important that you go through all of them to ensure that your account is configured to match your desired level of privacy. For now, simply choose the top option: “Account info privacy settings“.

If you look down the left side, there is quite a list of different privacy settings you can tweak, including perhaps two of the most important: what apps are accessing your camera and microphone? The bad news is that if you have malware on your system, it’s quite possible that there are apps stealthily accessing your camera, which is why we recommend a webcam cover of some sort.
Scroll down and you’ll see one of the options is “Contacts“. Click on it:

Now you want to scroll down on the right side of the window (yeah, this isn’t the easiest to figure out) until you see a list of apps:

Some of these apps make sense, like Messaging, but others can have you scratch your head. Why does Maps need access to your Contacts? (so you can search for addresses by name, if you’re curious). And, at the bottom, Xbox.
It’s easy to block access from an app, though. Just click the slider to “Off”:

This same basic approach works for all the other access permissions that your various programs and apps are requesting from the operating system, whether it’s your calendar, call history, microphone or camera. Take the time to check them all and set them as desired, and you’ll have regained a significant level of control over your Windows 10.1 privacy. Well done.

And, of course, anything the CIA installed. Good luck getting at those settings. :<P
Thanks, Dave. Didn’t know about this. As always, you’re the BEST!