How to Check Your Microsoft Defender Antivirus Signature Version in Windows 11

Keeping your antivirus definitions up to date is essential for protecting your PC against the latest threats. In Windows 11, Microsoft Defender Antivirus automatically updates its security intelligence (signature) database—but sometimes you may want to manually check your signature version. Perhaps you suspect an update failed, you’re troubleshooting a security alert, or you simply want to verify that your PC is protected with the latest threat data. This guide walks you through several simple methods to check your Microsoft Defender Antivirus signature version.

Method 1: Check Using Windows Security

The most straightforward method for most users is through the built-in Windows Security interface.

1. Click the Start menu and search for Windows Security, then open it. 

2. In the Windows Security window, select Virus & threat protection. 

3. Under Virus & threat protection updates, click Protection updates.

4. You will see your current Security intelligence version (e.g., 1.449.363.0). You can compare this number against Microsoft’s official latest release notes online to ensure you are completely current.

5. If your version is outdated, you can click Check for updates to download the latest security intelligence updates.

Method 2: Check Using PowerShell

For users who prefer a command-line approach, PowerShell provides quick access to this information.

1. Right-click the Start button and select Windows Terminal (Admin) or PowerShell (Admin). 

2. Type the following command and press Enter:

Get-MpComputerStatus | Select-Object AntivirusSignatureVersion

Method 3: Check Using Command Prompt

You can also retrieve the version using Command Prompt.

1. Press the Start button, type cmd, and choose Run as administrator.

2. In the Command Prompt window, type the following command and press Enter:

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

Method 4: Check Using Registry Editor

Advanced users can also find the antivirus signature version stored in the Windows Registry.

1. Press Win + R, type regedit, and press Enter. 

2. Navigate to the following path:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Signature Updates

3. In the right pane, locate the value named AVSignatureVersion. 

4. Double-click it to view the current antivirus signature version.

Concluion

Checking your Microsoft Defender Antivirus signature version in Windows 11 is quick and easy. Knowing how to check your signature version gives you a powerful layer of control and insight. Regularly verifying and updating your antivirus definitions ensures your system stays protected against the latest threats.