What is MpFilter?

The genuine MpFilter.sys file is a software component of Microsoft Malware Protection by Microsoft.
A background process for the Microsoft Malware Protection bundle, this application is a network filter. It protects Microsoft products from known malware traversing a network. Founded in 1975, Microsoft's flagship product is the Windows operating system, which is installed on over 90% of workstations worldwide.

MPFilter stands for Malware Protection Filter

MpFilter.sys is a Windows driver. A driver is a small software program that allows your computer to communicate with hardware or connected devices. This means that a driver has direct access to the internals of the operating system, hardware etc. The free file information forum can help you determine if MpFilter.sys is a Windows system file or if it belongs to an application that you can trust.

Run a free scan to check for MpFilter drivers in need of updating

MpFilter.sys file information

The process known as Microsoft antimalware file system filter driver belongs to software Microsoft Malware Protection by Microsoft (

Description: MpFilter.sys is not essential for the Windows OS and causes relatively few problems. The file MpFilter.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 165,264 bytes (36% of all occurrences), 193,552 bytes and 5 more variants. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The program is not visible. You can uninstall this program in the Control Panel. MpFilter.sys is a Microsoft signed file. It is not a Windows system file. The file has a digital signature. MpFilter.sys appears to be a compressed file. Therefore the technical security rating is 0% dangerous.

Uninstalling this variant: In case of problems with MpFilter.sys, you can also do the following:
  1) completely remove Microsoft Antimalware or Microsoft Security Client (Control Panel ⇒ Uninstall a Program)
  2) look for help on the website.

Recommended: Identify MpFilter.sys related errors

Important: Some malware disguises itself as MpFilter.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the MpFilter.sys process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


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Best practices for resolving MpFilter issues

A clean and tidy computer is the key requirement for avoiding problems with MpFilter. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the MpFilter.sys process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

MpFilter.sys [all]