Windows 10’s digital assistant is Cortana and, much like Siri, Google Assistant and Alexa, her usefulness depends on how much information you allow her to access.

Much like a real personal assistant, Cortana can only be truly useful if you give her permission to access your contacts and tell her about your relationships. A PA can’t tell you your wife is calling if she doesn’t know who your wife is, and it’s a similar situation with Cortana.

Allowing her to access your calendar, email and more means you’ll get better information when you ask Cortana a question such as “what’s on my schedule today” or “when is my flight to New York”.

Cortana can also combine various services, such as email and maps. Then, if there’s a traffic jam which would delay you on the way to the airport or a meeting, Cortana can notify you that you need to leave earlier than expected.

What does Cortana know about you?

But what does she actually know about you?

Microsoft has, over the years, given users more granular control over what they want Cortana can and cannot do. Here’s an overview of the information you can allow or deny her access to:

  • Your location
  • Your contacts, email, calendar and Messages history
  • Your browsing history (in Microsoft Edge)
  • Your device’s microphone, typing history and handwriting patterns
  • Places you visit, plus your home and work locations
  • Information from any connected services you approve

Some of these are grouped, as you can’t enable or disable access to individual services: it’s all or nothing.

When you disable any of these things, Cortana stops collecting that information, but keeps what she has already ‘learned’.

To get an overview of what she knows, take a look at the Notebook. Click in the search box next to the Start button in Windows, then on the square icon with a little circle in it, just below the home icon.

What does Cortana know about you?

This shows which account is signed in, and is divided into Organiser and Manage Skills tabs.

Organiser includes your lists and reminders. Manage Skills lets you connect services to Cortana, and see which ones are already linked. Here you can toggle on or off notifications for services such as weather, flights, meetings, news and sports headlines.

You can read Microsoft’s Privacy Statement to find out more about what it does with the collected data.

Bear in mind that what Cortana knows is dependent upon the device you’re using, which is probably Windows. But there’s also the Cortana app for Android and iPhone, which doesn’t know quite so much. Yet, if you do use Cortana it makes sense to install the app on your phone in order to get reminders when you’re not using your PC or laptop.

We’ve got a separate guide on how to use the Cortana app

How can I delete what Cortana knows?

You can clear Cortana’s history – all the information about you she has stored - by clicking in the Windows 10 Search box, then on the Settings cog.

What does Cortana know about you?

Click on Permissions & History, then ‘Change what Cortana knows about me in the cloud’.

What does Cortana know about you?

This will open up the Cortana menu at the bottom-left of the screen. Scroll down and you’ll see a ‘Clear’ button under the ‘Clearing your personal info’ section.

Click it and the button will change to ‘Your recommendations have now been cleared’.

What does Cortana know about you?

You can also clear the data held in the cloud by logging into your Microsoft account on Microsoft’s website 

Plus, you might like to know What Google knows about you.