Microsoft Defender Antivirus is the built-in antivirus program in Windows 11 that helps keep your computer safe from viruses and other harmful software.

Microsoft updates Defender regularly with new “signature versions.” These updates help Defender recognize and stop the latest threats quickly.

It’s a good idea to check which signature version you have. This tells you if your antivirus is up to date and ready to protect you.

Method 1: Check Signature Version in Windows Security

1. Click the Start button and type Windows Security, then open the app.
2. In Windows Security, click on Virus & threat protection.
3. Look for the section called Virus & threat protection updates, then click Protection updates.
4. You will see your current Security intelligence version (this is the signature version).

Here’s an example screenshot to help you find it:

Method 2: Check Signature Version Using Command Prompt or PowerShell

1. Right-click the Start button and choose Windows Terminal (or open Command Prompt or PowerShell).
2. Copy and paste the command below, then press Enter:

Get-MpComputerStatus | select AntivirusSignatureLastUpdated,AntivirusSignatureVersion

If you’re using Command Prompt, use this command instead:

powershell -command "Get-MpComputerStatus | select AntivirusSignatureLastUpdated,AntivirusSignatureVersion"

This will show you the date your antivirus was last updated and the signature version number.

Why This Matters

• Automatic Updates: Defender updates itself automatically, but it’s good to check the version sometimes.
• Security: The signature version tells you how current your protection is.
• Easy to Check: Use the Windows Security app or a quick command—both work well!
• Stay Safe: Knowing your signature version helps you be sure your PC is protected.

For more info or to see the latest updates from Microsoft, check these links:

• Latest Microsoft Defender Antivirus Updates
• Antimalware Definition Release Notes

That’s all! Now you know how to check your Microsoft Defender Antivirus signature version on Windows 11.