Important: The National Public Data breach exposed personal information, including names, addresses, and social security numbers. Learn how to protect yourself and how Microsoft Defender is helping to prevent fraud. See: National Public Data breach: What you need to know.
Microsoft Defender is the simple way to protect your digital life and all of your devices. It's included as part of your Microsoft 365 Family, or Personal, subscription at no extra cost.
Important: This article is about the Microsoft Defender app that is included with Microsoft 365 Family or Personal subscriptions. If you're looking for information about the Microsoft Defender antivirus that is built into Microsoft Windows, see Stay protected with Windows Security.
If you haven't installed Defender on your devices yet, follow the steps in Installing Microsoft Defender.
Microsoft Defender is a security app that helps people and families stay safer online with malware protection, web protection, real-time security notifications, and security tips. Microsoft Defender is included in a Microsoft 365 Family or Personal subscription and works on your phone (Android or iOS), PC, and Mac.
Windows Security, formerly known as Windows Defender Security Center, is an app built into Windows 10 or 11 that helps keep your PC more secure. It includes Microsoft Defender Antivirus, an antivirus tool that helps protect you against viruses, ransomware, and other malware.
For more information, see Stay protected with Windows Security.
Windows Defender Firewall is firewall software built into Windows that controls which network traffic is allowed, or blocked, from passing to or from your computer across the network. Windows Defender Firewall is on by default.
Anti-malware
Malware is malicious software which can steal or damage your personal data such as files, photos, or messages. It may also track or spy on you, steal your money, or use your device to cause other mischief like attacking other people.
On Windows, Mac, and Android Microsoft Defender can check files or apps you download and install, as well as run scans of files already on your system to spot any malware that may threaten your device.
To learn more about anti-malware see Getting started with anti-malware in Microsoft Defender.
Tip: Stay up-to-date and install the latest updates on all your devices and apps (especially browsers) to help prevent malware.
Microsoft Defender works alongside your existing antimalware solutions, even if they're made by other companies such as Norton or Bitdefender.
Web protection
Many of the digital attacks we see are through harmful websites that try to trick you into revealing personal information—such as usernames and passwords, credit cards, or other account information—or installing malware on your system. On Windows, iOS, and Android Microsoft Defender will check links that you (or an app on your device) open to try and spot any that may be dangerous.
If we find a harmful link, we'll block it and let you know.
To learn more about web protection in Microsoft Defender, see Getting started with web protection.
Tip: What is phishing? It’s a trick to steal your info or get you to install malware by pretending to be a message from someone you trust. For more information see Protect yourself from phishing.
Identity theft monitoring
We’ve partnered with Experian® to bring world class identity theft monitoring to Microsoft Defender. This feature allows you to monitor your own identity details, as well as your family’s, for breaches on both the public internet and the dark web.
Important: Identity theft monitoring is currently only available to customers in the United States.
If we spot your personal details in a breach, you’ll receive an alert and a detailed breach report telling you exactly what data was found and where. You'll get recommendations on what to do right away to address the situation, details on how this might have happened, information on the possible risks, and tips on how to reduce the chances of it happening again.
You also get 24/7 phone access to a team of highly skilled identity theft professionals who can guide you through the process of addressing the breached details or provide full-service identity restoration services in the event an identity thief is using your personal details to commit fraud.
To learn more see Getting started with identity theft monitoring in Microsoft Defender.
Adding other devices
You can add up to 4 additional devices (for a total of 5 per person) to your Microsoft Defender account by installing the app on your other devices and signing in using the same personal Microsoft account. These devices will appear on your Microsoft Defender dashboard so you can see the security status of all your devices in one place.
For more information, see Adding devices to your Microsoft Defender account.
Helping to protect the whole family
If you're a Microsoft 365 Family subscriber, the people who have the Family Organizer role can help to protect the devices and identities of everybody in the family. When other family members install Microsoft Defender and choose to share their device security or identity monitoring status, the family organizers will see that status on their Microsoft Defender dashboard.
For more information, See your family's devices in Microsoft Defender.
We'd love to hear from you!
Your feedback is key to making our products better, so if there's anything you like about Microsoft Defender, and especially if there's anything you don't like, please let us know! You can send us feedback in the app by going to the Help and feedback menu.
On Windows or Mac, select the  
Visit the Microsoft Defender community on Microsoft Answers!
Want to ask, or answer, questions about Microsoft Defender? Chat with others who are using Defender? Visit the Microsoft Answers community for Microsoft Defender here!
