Windows Defender Antivirus Definition Updates for timely updating of your Windows Defender if the automatic update happens to fail. Video tutorial available.

Installation instructions for Windows Defender Definition Updates:

Step 1: Save or run the file

After you click this link, click Run to install the definition file immediately or click Save to save it to your computer. If you click Save, remember the name of the folder where you save the file.



Step 2: Install the definition update.

To install the saved definition update file:

If your computer runs Windows Vista, click Start, click Documents, and then locate the folder where you saved the definition file. Right-click Mpas-fe.exe, click Run as administrator and then click Run. When you are prompted for an administrator password or confirmation, type the password or provide confirmation, and then wait while the definition files are installed.

If your computer runs any other Windows operating system, you must be logged on as an administrator to install the latest definition file. Browse to the folder where you saved the file, and then double-click Mpas-fe.exe to install the latest definition file.

If the update fails, you can update from the Command Prompt:

Open Command Prompt or Powershell and type in the following two lines, pressing Enter after each:

cd "\Program Files\Windows Defender"

.\mpcmdrun.exe -signatureupdate

Consider using Malwarebytes for complete antivirus protection and to protect your devices, data, and privacy.

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