How to Check Your Windows Defender Version on Windows 10

Windows Defender (now officially called Microsoft Defender Antivirus) is the built-in security component of Windows 10. Keeping it current is essential because new virus definitions and engine updates are released almost daily. In this guide we show you exactly how to verify which version of Defender is running on your PC, how to read each of the three version numbers and how to make sure they are all up to date in 2026.

Why the Defender Version Matters

Microsoft Defender relies on three separate version numbers that work together:

  • Antimalware client version - the main Defender application installed on your system.
  • Engine version - the scanning engine that analyses files and behaviour.
  • Security intelligence version - the signature database listing known threats.

An outdated engine can miss modern evasion techniques, while stale signatures leave gaps against recently discovered malware. Checking all three numbers takes less than a minute and can save you from a nasty surprise. If you are unsure which edition of Windows you are running first, our short guide on checking your Windows version (32-bit or 64-bit) pairs nicely with the steps below.

Method 1: The Windows Security App

This is the friendliest route and works on every genuine copy of Windows 10.

  1. Open Settings > Update & Security > Windows Security.
  2. Click Virus & threat protection.
  3. Scroll down and select Virus & threat protection updates (or Check for updates).
  4. Windows will display the security intelligence version, the date it was created, and the engine and client version numbers.

If any of the numbers look old, click Check for updates on the same screen to pull the latest definitions directly from Microsoft.

Method 2: PowerShell (Fastest)

For a quick, scriptable check, open PowerShell as administrator and run:

Get-MpComputerStatus | Select AntivirusSignatureVersion, AMEngineVersion, AMProductVersion

This returns the three key version numbers on a single line. PowerShell also exposes plenty of other useful fields - try Get-MpComputerStatus on its own to see the last scan time, real-time protection state and tamper protection status in one go.

Method 3: Command Prompt

If you prefer CMD, run the following as administrator:

"%ProgramFiles%\Windows Defender\MpCmdRun.exe" -SignatureUpdate

This forces an update and prints the current versions. Power users can also use MpCmdRun.exe -Scan to launch a manual scan from the command line, which is handy when you are troubleshooting a machine remotely.

How to Update Windows Defender

Defender updates arrive through Windows Update. Open Settings > Update & Security > Windows Update and click Check for updates. You can also trigger a signature update manually using the PowerShell command above, or from the tips in our best Windows 10 productivity tools article. If Windows Update is stuck, make sure your Windows licence is properly activated - an unactivated copy can silently fall behind on security patches, as we explain in 7 things that happen if you don't activate Windows 10.

When to Consider a Third-Party Antivirus

Windows Defender scores well in independent lab tests and is perfectly adequate for most home users. If you need centralised management across multiple endpoints, advanced sandboxing or a dedicated firewall, a third-party suite may be a better fit. Our best Windows antivirus programmes roundup compares the leading options side by side.

Keep Windows Itself Up to Date

An up-to-date Defender is only as strong as the operating system it runs on. Make sure your Windows installation is fully patched, and consider upgrading to Windows 11 Pro if your hardware supports it - the newer platform ships with tighter default security, including virtualisation-based protection and improved tamper resistance.

Quick Checklist

  • Open Windows Security and confirm all three version numbers are recent.
  • Run Get-MpComputerStatus in PowerShell for a scriptable snapshot.
  • Run Windows Update weekly, or enable automatic updates.
  • Keep your Windows licence activated so you continue to receive security patches.
  • Review your antivirus strategy once a year, especially if you manage several PCs.

A two-minute version check today is cheaper than hours of malware cleanup tomorrow. Make it part of your monthly routine and your Windows 10 PC will stay protected against the latest threats.

Best regards,
The Licendi Team