Download Details

Version: 102.2608.18002.0 (latest)
File size: 15.17 MB
License: Free
Security scan: VirusTotal: 71 of 71 engines say OK (0 flagged)
Developer: Microsoft Corporation
Supported OS: Windows 11, Windows 10
Installers: 64-bit (x64), 32-bit (x86), ARM (Arm64)
Downloads: 8571
Rating: 4.9 out of 5 · 92 reviews

Reviewed by Eman Sakr
Tested on Windows 11 and 10 · November 4, 2026 · How we review

Screenshots

Microsoft Defender is the free antivirus from Microsoft, built to protect Windows 11 and Windows 10 PCs in the background.

It suits anyone who wants solid everyday protection without extra subscriptions, popups or upsells.

It is worth having on for most home users. Real-time scanning, cloud-delivered updates and ransomware safeguards cover the basics well.

What it lacks are extras such as a VPN or a password manager.

What is Microsoft Defender?

Microsoft Defender is Microsoft’s own antivirus for Windows. It started life as a small anti-spyware tool and grew into the default protection that ships with Windows 10 and Windows 11.

You manage it through the Windows Security app, which also groups firewall, app control and device health settings in one place.

Real-time protection

Real-time protection watches files, downloads and running programs for malware, viruses and ransomware. Cloud-delivered protection checks suspicious files against Microsoft’s online intelligence, which helps with brand-new threats.

Tamper Protection is on by default. It stops malicious apps from quietly switching off key Defender settings such as real-time protection.

Tip: If you want a free antivirus that keeps your PC responsive, leave Defender’s default settings alone and let Windows Update handle the rest.

Scan options

Windows Security offers a quick scan, a full scan, a custom scan and a Microsoft Defender Offline scan. You can also right-click a file or folder and scan it on the spot.

The offline scan restarts your PC and checks it before Windows fully loads, which helps against stubborn malware that hides while the system is running.

Tip: If the same infection keeps coming back after a normal scan, run the offline scan, then check Protection history for what was found.

Do you need a separate Defender offline download?

No. On current Windows 10 and Windows 11, the offline scan is part of the Windows Security app. There is no extra tool to install for it.

Where it can annoy you

Defender sometimes flags safe programs, especially small utilities and freshly compiled software. You can review the detection in Protection history and allow the file if you trust it.

Fine-tuning the settings, such as exclusions or controlled folder access, takes a little know-how.

Tip: If scans slow your PC down, run a full scan when you are away from the computer instead of mid-work.

Who should skip it

Skip Defender if you want extras bundled into one package, such as a VPN, a password manager, parental controls or breach monitoring.

It is also not the best fit if you want a dashboard with many tuning options right in the main window.

How to Download & Install

Click the download button at the top of this page to get the EXE installer.

Step 1: Click the download button at the top of this page and save the installer.
Step 2: Double-click the installer and approve the Windows permission prompt.
Step 3: Follow the on-screen prompts until setup finishes.
Step 4: Open the Start menu, search for Windows Security and check that Virus & threat protection shows no warnings.

Installer types

This page offers one main installer, usually the 64-bit build.

The app also supports 32-bit (x86) and Arm64 devices.

System requirements

Windows 11 or Windows 10
64-bit (x64), 32-bit (x86) or Arm64 processor
Administrator rights for installation

License and activation

Microsoft Defender is free to use. There is no key to enter and no activation step.

How to update

Defender receives its threat definitions (security intelligence updates) through Windows Update, usually several times a day.

To check by hand, open Windows Security, go to Virus & threat protection, select Protection updates, then click Check for updates.

Fixes for common problems

Real-time protection toggle is grayed out: Tamper Protection or another installed antivirus is usually the cause. Sign in as an administrator, turn Tamper Protection off briefly, then switch Real-time protection on and re-enable Tamper Protection.
Installer will not run: Another security product may be blocking it. Pause that product, run the installer as an administrator, then turn it back on.
Wrong build for your PC: If the installer reports an incompatibility, check whether your PC is 64-bit, 32-bit or Arm64 under Settings, System, About.

Pros & Cons

What we liked

Completely free to use
Real-time malware and ransomware protection
Updates arrive through Windows Update
Built-in firewall and Tamper Protection
Includes a boot-time offline scan

What we didn't like

No VPN or password manager
Occasional false positives on safe software
Advanced settings take some know-how

Best Microsoft Defender Alternatives

Bitdefender Antivirus Free
Free antivirus with real-time malware, ransomware and phishing protection, light on resources.
Avira Free Security
Free antivirus with real-time protection, a limited VPN and PC cleanup tools.
Kaspersky Free
Cloud-assisted real-time malware scanning and anti-phishing protection at zero cost.
Malwarebytes
Free malware scanner that removes ransomware, spyware and adware without slowdown.

Conclusion

4.9out of 5 · 92 user ratings

Defender is a solid default, but it is worth seeing how it sits next to other free options.

Look at price, extra tools and how much control you want over the settings.

App	Best For	Price	Platform	Standout Feature
Microsoft Defender	Everyday protection with zero setup	Free	Windows 11, Windows 10	Built-in protection with Tamper Protection and offline scan
Bitdefender Antivirus Free	Light, set-and-forget protection	Free (paid suites available)	Windows	Cloud-based scanning with a small footprint
Malwarebytes	A second opinion and cleanup	Free scanner (paid Premium available)	Windows, macOS, Android, iOS	Strong on-demand malware removal
Avast Free Antivirus	Users who want extra tools included	Free (paid tiers available)	Windows, macOS, Android	Free tier with added security tools

Final verdict

Microsoft Defender gives most Windows users dependable, free protection without extra installs or subscriptions.

If you want a VPN, a password manager or parental controls in the same package, a paid suite makes more sense.

FAQ

Is Microsoft Defender good enough on its own?

For most home users, yes. It offers real-time protection, cloud-delivered updates, ransomware safeguards and a built-in firewall.

You only need more if you want extras like a VPN or password manager.

Is Microsoft Defender free?

Yes, Microsoft Defender Antivirus is free and comes with Windows 10 and Windows 11. There is no key and no activation step.

Do I need to download Microsoft Defender on Windows 11?

Windows 11 already includes Defender Antivirus through the Windows Security app. Use the installer on this page if you need to restore or reinstall it.

How do I run a Microsoft Defender offline scan?

Open Windows Security, go to Virus & threat protection, select Scan options, choose Microsoft Defender Antivirus (offline scan), then click Scan now.

Your PC restarts and scans before Windows loads, and you can read the results under Protection history.

How do I update Microsoft Defender?

Defender updates through Windows Update. To check manually, open Windows Security, go to Virus & threat protection, select Protection updates and click Check for updates.

Why can’t I turn on real-time protection?

Tamper Protection or another installed antivirus is usually the reason. Sign in as an administrator, turn Tamper Protection off briefly, enable Real-time protection, then turn Tamper Protection back on.

Is Microsoft Defender safe to install?

Yes. The file was checked with VirusTotal and came back clean, and it comes from Microsoft Corporation.

Found a problem with this download? Report an outdated version, broken link, suspicious installer or incorrect information.

Microsoft Defender