Microsoft continually updates security intelligence in antimalware products to cover the latest threats and to constantly tweak detection logic, enhancing the ability of Windows Defender Antivirus and other Microsoft antimalware solutions to accurately identify threats. This security intelligence works directly with cloud-based protection to deliver fast and powerful AI-enhanced, next-generation protection.

• Windows Defender Definitions Download

• Trigger an update A manually triggered update immediately downloads and applies the latest security intelligence. This process might also address problems with automatic updates. Windows Defender Antivirus and other Microsoft antimalware solutions provide a way to manually trigger an update.
• Jun 30, 2017  Original Title - WINDOWS DEFENDER. Does the 'latest' WINDOWS DEFENDER DEFINITION UPDATE super-cede all previous updates? Two DEFINITION Updates (May 2 - 2013; May 11 - 2013) FAILED to be installed by Windows Automatic Updates. I am now instructed to MANUALLY Install these Definitions. I do not know HOW to MANUALLY Install these Definitions.

Microsoft security intelligence updates include software that incorporates material from third parties. Third-party notices and information

Automatic updates

To help ensure your antimalware solution detects the latest threats, get updates automatically as part of Windows Update. If you are having problems with Windows Update, use the troubleshooter.

Apart from these options, Microsoft makes it easy to download and install Windows Updates such as Cumulative Updates and Windows Defender definitions manually. This article shows you how to do it.

If you don't already use Windows Defender Antivirus, learn how to turn it on.

Trigger an update

A manually triggered update immediately downloads and applies the latest security intelligence. This process might also address problems with automatic updates. Windows Defender Antivirus and other Microsoft antimalware solutions provide a way to manually trigger an update.

In Windows 10, select Check for updates in the Windows Security Virus & threat protection screen to check for the latest updates.

Enterprise administrators can also push updates to devices in their network. To clear the current cache and trigger an update, use a batch script that runs the following commands as an administrator:

Manually download the update

You can manually download the latest update.

Latest security intelligence update

The latest security intelligence update is:

• Version: 1.303.908.0
• Released: 10/5/2019 2:22:54 AM
• Documentation: Release notes

You need to download different security intelligence files for different products and platforms. Select the version that matches your Windows operating system or the environment where you will apply the update.

The links point to an executable file named mpam-fe.exe, mpam-feX64.exe, or mpas-fe.exe (used by older antispyware solutions). Simply launch the file to manually install the latest security intelligence.

End of life for Microsoft Forefront Client Security was on July 14, 2015. Customers are encouraged to migrate to System Center Endpoint Protection. For more information, visit the Microsoft support lifecycle website.

Network Inspection System updates

The following products leverage Network Inspection System (NIS) updates:

• Microsoft Security Essentials
• Forefront Endpoint Protection
• System Center 2012 Endpoint Protection

These updates are designed to protect you from network threats, including exploits as they are transmitted. Check the version of the Antimalware Client component on your security software and download the right version of the NIS updates for your platform.

Windows Defender Definitions Download