Install the latest Windows Defender definition updates

Install the latest Windows Defender definition updates for computers running x32-based version of Windows

For more information please review the Knowledge Base Article: How to manually download the latest definition updates for Windows Defender.

If you encounter problems while trying to install definition updates for Windows Defender, you can download the latest Windows Defender definition updates for computers running a 32-bit (x86-based) version of Windows.

Step 1: Save or run the file.
After you download the latest definition updates, 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 is running Windows Vista or Windows 7, 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 is running 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.

Note: If you do not have an administrator account on the computer, ask an administrator to log on and install the definitions file for you.

For more information on how to manually download the latest definition updates for Windows Defender, review the Knowledge Base article: How to manually download the latest definition updates for Windows Defender.

Install the latest Windows Defender definition updates for computers running x64-based versions of Windows

Download and install definition updates for Windows Defender on computers running x64-based versions of Windows.

Note: You must be running an x64-based version of Windows to run an x64-based version of Windows Defender. For more information, please visit the Windows Defender website.