Download Microsoft Defender for PC, Windows 11/10 & Mac

Microsoft Defender reaches your machine two ways. Windows Security, which holds Microsoft Defender Antivirus and Windows Firewall, is already on every Windows 11 and Windows 10 PC at no cost. The separate Microsoft Defender app installs from the Microsoft Store and covers Mac, iPhone and Android too.

That second app is the one with identity theft monitoring and a family dashboard, and Microsoft sells it only inside a Microsoft 365 Personal, Family or Premium subscription.

This guide covers which of the two you need, the official links and sizes, the install steps on Windows and Mac, and fixes for the common failures.

What are the Microsoft Defender system requirements?

Every figure below comes from Microsoft’s Store catalog entry.

Windows 10 PCs below build 22000 receive package 102.2602.23001.0 instead, at 135.3 MB for x64.

Which Microsoft Defender download do you need?

Match your device and your subscription status in the table.

Identity theft monitoring and credit monitoring cover the United States and US territories only, and Microsoft states the app is not available in certain regions.

Download Microsoft Defender from the official Microsoft source

The publisher line on the Store listing reads Microsoft Corporation.

1. Microsoft Defender on the Microsoft Store, product 9P6PMZTM93LR — 15.2 MB, x64 and x86
2. Microsoft’s Defender page, with buttons for Windows, Mac, Android and iOS — the Mac route starts here
3. Microsoft Defender: Security on the App Store — 158.0 MB, iOS 17.0 or later
4. Security intelligence updates for Microsoft Defender Antivirus — definition 1.459.335.0, mpam-fe.exe
5. The Windows Security app documentation — built in, no download

There is no standalone .exe for the app. The Windows build ships as a Store package, so setup needs an internet connection.

How to install Microsoft Defender on Windows 11 and 10

Activate the Microsoft 365 subscription first. The app signs you out again without one.

1. Open Microsoft Store from the Start menu.
2. Search for Microsoft Defender, or open product 9P6PMZTM93LR from the link above.
3. Check that the publisher line reads Microsoft Corporation.
4. Select Get, then wait for the 15.2 MB package to install.
5. Select Open, then Sign in.
6. Enter the Microsoft account that holds your Microsoft 365 Personal, Family or Premium subscription.
7. Work through the dashboard prompts to add the devices and the personal details you want watched.
8. Right-click the app on the taskbar and select Pin to taskbar.

The app sits beside Windows Security rather than replacing it, extending protection to your Android, iOS and macOS devices.

Install Microsoft Defender with winget from a terminal

The Store product ID doubles as the winget package ID.

1. Right-click Start and select Terminal.
2. Run winget install 9P6PMZTM93LR –source msstore .
3. Type Y the first time winget asks you to accept the Store source agreement.
4. Wait for Successfully installed, then open the app from Start and sign in.

Add –accept-package-agreements –accept-source-agreements to run the line from a script without prompts.

Which Microsoft Defender download do you need for your Mac?

macOS has no Mac App Store listing for this app. The download button on Microsoft’s own page is the route.

Sign in on the Mac with the account used on the PC, and one dashboard lists every device.

Is Microsoft Defender free?

Half of it is free and half of it is not. Windows Security, with Microsoft Defender Antivirus and Windows Firewall inside it, ships with Windows 11 and Windows 10 and costs nothing. The Microsoft Defender app is a different product, available exclusively with a Microsoft 365 Personal, Family or Premium subscription at $99.99, $129.99 and $199.99 per year. No licence key is sold on its own.

The subscription carries identity cover of up to USD 1 million for restoration-related legal and expert fees, and up to USD 100,000 for lost funds recovery.

Which one do you need: Windows Security or the Defender app?

Install the app only if you already pay for Microsoft 365. Windows Security handles the antivirus, firewall, SmartScreen and device security work on its own, and Microsoft states the PC is protected from the moment it starts up. The app adds identity theft monitoring, credit monitoring and one dashboard across Windows, Mac, Android and iOS.

The two run together, and Microsoft describes the app as working with built-in Windows Security.

What each Windows Security area covers

Open the app from the shield icon on the taskbar, from a Start menu search, or from Settings > Privacy & security > Windows Security.

Options grey out on a work PC because group policy and Intune settings take precedence.

How to check your Microsoft Defender version and update it

Protection updates normally arrive through Windows Update.

1. Search the Start menu for Security and open Windows Security.
2. Select the Virus & threat protection tile.
3. Select Virus & threat protection updates to read the installed version and its download date.
4. Select Check for updates to pull anything newer.
5. Compare the number against the current release on Microsoft’s security intelligence page, which lists 1.459.335.0.
6. For the app itself, open Microsoft Store > Library > Get updates.

A PC with no internet connection takes the manual package instead. The x64 file mpam-fe.exe is 206.2 MB, the x86 file is 205.5 MB and the ARM64 file is 205.7 MB.

How to make Microsoft Defender Antivirus active again on Windows 11

Windows disables Microsoft Defender Antivirus automatically when another antivirus is installed and kept up to date.

1. Open Settings > Apps > Installed apps and uninstall the third-party antivirus.
2. Restart the PC.
3. Open Windows Security, then Virus & threat protection.
4. Select Who’s protecting me?, then Manage Providers, and confirm the page names Microsoft Defender Antivirus.
5. Select Virus & threat protection settings, then Manage settings, and set Real-time protection to On.
6. Open a terminal and run Get-MpComputerStatus , then read the AMRunningMode row.

Normal in that row means active mode. Passive mode and SxS Passive Mode mean another product is in charge.

Fix Microsoft Defender not installing or not turning on

Work through the symptom that matches.

The Store install fails or stalls

The Store client or Windows itself is behind the package’s minimum build.

1. Open Settings > Windows Update and install everything waiting, then restart.
2. Check your build with winver : the newest package needs Windows 11 build 22000 or later.
3. Open Microsoft Store > Library > Get updates to refresh the Store.
4. Retry the install, or run winget install 9P6PMZTM93LR –source msstore .

The app signs you straight back out

The account has no Microsoft 365 Personal, Family or Premium subscription attached.

1. Sign in with the account that owns the subscription, not a second Microsoft account.
2. On a family plan, accept the organiser’s invitation before signing in.
3. Check the region: Microsoft states the app is not available in certain regions.

Real-time protection is greyed out

A third-party antivirus is installed, or a policy controls the setting.

1. Open Windows Security > Virus & threat protection > Manage Providers and read which product is listed.
2. Uninstall the third-party antivirus from Settings > Apps > Installed apps if you want Microsoft Defender Antivirus back in charge.
3. On a work PC, ask your administrator: group policy and Intune settings override the local toggle.

The offline scan does nothing

The Windows Recovery Environment is disabled, so the scan never boots.

1. Open a terminal as administrator and run reagentc /info .
2. If the status reads Disabled, run reagentc /enable .
3. Suspend BitLocker on the system drive to avoid a recovery key prompt at restart.
4. Save your files, then run the scan from Virus & threat protection > Scan options > Microsoft Defender Offline scan > Scan now.
5. Expect about 15 minutes and one restart before Windows loads normally.

The offline scan applies to x64 Windows 11 and to x64 or x86 Windows 10. Microsoft documents that it does not apply to ARM Windows or to Windows Server.

How to uninstall the Microsoft Defender app

Removing the app leaves Windows Security untouched. Microsoft documents that Windows Security cannot be uninstalled at all.

1. Open Settings > Apps > Installed apps.
2. Find the entry, select the three dots beside it, then select Uninstall.
3. Confirm Uninstall in the prompt.
4. Open Windows Security and check the shield still reports the PC as protected.
5. On the Mac and phones, remove the app the usual way for each platform.

Identity monitoring stops for the devices you remove, and the subscription runs until you cancel it.

Which other Microsoft Defender product fits your situation?

Four products share the Defender name.

The Microsoft Defender Security Center web portal belongs to the enterprise product. It is not the Windows Security app on your PC.

Frequently asked questions

Is Microsoft Defender free?

Windows Security is free and built into Windows 11 and Windows 10, and it holds Microsoft Defender Antivirus and Windows Firewall. The separate Defender app is sold only inside a Microsoft 365 Personal, Family or Premium subscription.

What is the official Microsoft Defender download page?

The Microsoft Store listing for product 9P6PMZTM93LR on Windows, and the Download for MacOS and Download for iOS buttons on Microsoft’s own Defender page. Windows Security has no download page.

Does Microsoft Defender work on Windows 11?

Yes. The newest Store package needs Windows 11 build 22000 or later, and Windows 10 PCs from build 19041 receive an older package. Windows Security runs on both with no install.

How big is the Microsoft Defender download?

The current Windows package is 15.2 MB for x64 and 14.3 MB for x86, taking 41.1 MB once installed. The iPhone and iPad build is 158.0 MB.

Is there a Microsoft Defender offline installer or .exe?

No. The Windows app ships only as a Microsoft Store package, so setup needs an internet connection. The one file Microsoft publishes is the security intelligence update, mpam-fe.exe, at 206.2 MB for x64.

Is there a Microsoft Defender app for Mac?

Yes, for Microsoft 365 subscribers. Microsoft’s Defender page carries a Download for MacOS button and describes the Mac build as adding antivirus and identity theft monitoring. No Mac App Store listing exists.

Does Microsoft Defender support ARM64 PCs?

The Store app lists x64 and x86 packages only, with no ARM64 build. Windows Security still ships on ARM64 PCs, though Microsoft documents that the offline scan does not apply to ARM Windows.

Is Microsoft Defender safe to download?

Take it from the Microsoft Store listing published by Microsoft Corporation, or from the buttons on Microsoft’s own Defender page. Both install a signed package. Files from download portals are repackaged copies.

What is the latest Microsoft Defender version?

Package 102.2602.23002.0 is the newest Windows build in Microsoft’s Store catalog. Security intelligence stands at 1.459.335.0, with engine 1.1.26080.3 and platform 4.18.26080.4.

Why won’t Microsoft Defender install?

Usually the PC sits below build 22000, the Microsoft Store is out of date, or Windows updates are pending. Install those updates, restart, refresh the Store from Library, then retry.

Do I need a Microsoft 365 subscription for Microsoft Defender?

For the app, yes. Microsoft lists it as available exclusively with a Microsoft 365 Personal, Family or Premium subscription. The antivirus inside Windows Security needs no subscription and no sign-in.

What happens to Microsoft Defender when I install another antivirus?

Windows disables Microsoft Defender Antivirus automatically once the other product is installed and kept up to date. Windows Security keeps running and still reports the firewall and SmartScreen status.

Can I uninstall Windows Security?

No. Microsoft documents that the Windows Security app cannot be uninstalled. Administrators can hide its sections or disable Microsoft Defender Antivirus by policy, but the app stays part of Windows.