Installing Microsoft Defender - Microsoft Support (2023)

Run in the background

A security tool that only works sometimesisn't nearly as effective. You wantMicrosoft Defenderto always watchyour back, protecting you from the malicious sites you weren't expecting. In order to do that, Defender needs permission to run in the background.

Accessibility service

In order to make sure the site you're going to isn't known to be dangerous, Defender needs to be able to see the address. To do that onAndroid, we use the Accessibility Serviceto read, almost literally, the address from your browser.

Important:Only one app at a time can have permission to use the Accessibility Service. If you give that permission to a different app, web protection in Defender will be turned off.

After setting up web protection, we'll set up anti-malware protection. To do this we need to ask for a couple more permissions.

Access device storage

Microsoft Defenderscans apps and files on your device to watch for possible threats. To do that, it needs to be able to access those files. We only use that permission to look for malicious apps, aprocess that happens entirely on your device. No information about your apps or files is sent to Microsoft.

Send notifications

If you wantMicrosoft Defenderto tell you if we find a threat, you'll need to allow us to send you notifications on your device.

Run in the background

Note:If you already allowedMicrosoft Defenderto run in the background for web protection, you won't be asked for this permission again.

Protecting your device is a full-time job, but you probably want to use your device for other things, like texting, gaming, work, andentertainment. By allowingMicrosoft Defenderto run in the background, you allow us to help keep you safer all the time.

Let's finish with a scan

Finally, Microsoft Defenderwill run an initial scan of your device to see if there are threats already on it. This scan usually only takes a minute or two.

If that initial scan finds any threatsMicrosoft Defenderwill notify you and help you remove them.

A local VPN?

Dueto the built-in security settings in iOS, other apps aren't able to see the address (URL)an app is trying to open, including thosebeing opened in the web browser. To make sure the site you're going to isn't known to be dangerous, Defender needs to be able to see the address.

To do that, we set up a local VPN. It's called a local VPN because it never leaves your device—it's just a connection between your browser and Microsoft Defender running on your device.

When you click on a link, the browser sends the address you're going to through that local VPN to Defender.Defender checks the addressand then(assuming it's good), lets the browser open that site. The whole thinghappens so quickly you won't even notice.

Allow notifications

If the site is found to be maliciousthat's where notifications come in. We block access to the site, but iOS won't let us notify you of the problem in the browser, so instead we send you anotification telling you that the site you're trying to go to is dangerous. From that notification you can close the browser taband stay safe. Or, if you're completely sure that the site is safe,you can choose to continue to the site anyway.

Important:You can choose not to allow notifications and web protection will still work, but you won't get the notification that it was Defender who blocked the site you were trying to go to.

System access

To start with, we'll have you open the Security settings, then follow these steps:

1. Select the padlock at the bottom left so you can make changes. You'll be prompted to enter your password or other authentication.

2. You should see a prompt that says that Some system software requires your attention before it can be used.Select the Detailsbutton.

3. If you see a dialog asking you to select Microsoft Defender and Microsoft Defender Extension, select both and then OK.

Note:If you're using macOS Catalina (10.15) you maysimply see an Allow button, rather than Details.

Once that's done, select the padlock again to prevent further changes.

Access files

Next, we'll need permission to access your files.Microsoft Defenderscans apps and files looking for threats and it can only do that if it has permission to access the files. We'll ask you to select Open Privacy Settings, then follow these steps:

1. Select Full Disk Access.

2. Select Microsoft Defender and (if you see it)Microsoft Defender Extension.

Let's finish with a scan

Finally, Microsoft Defenderwill run an initial scan of your device to see if there are any threats already on it. That scan may take a while—depending on the speed of your device and how many apps you have—but you can keep using your computer while the scan runs in the background.

If that initial scan finds any threatsMicrosoft Defenderwill notify you and help you remove them.

Tip:IfMicrosoft Defenderis successfully installed and running, you'll see its icon on the title bar near the clock at the top right.