What is filter?
Filter.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 filter.sys is a Windows system file or if it belongs to an application that you can trust.
Run a free scan to check for filter drivers in need of updating
Filter.sys file information
The process known as WDM NULL filter driver or sys belongs to software Windows (version 2000 DDK driver) or sys by Walter Oney Software (www.oneysoft.com) or Windows (windows.microsoft.com) (version 2000 DDK provider) or Apple Computer inc.
Description: Filter.sys is not essential for the Windows OS and causes relatively few problems. Filter.sys is located in the C:\Windows\System32\drivers folder.
Known file sizes on Windows 10/8/7/XP are 8,832 bytes (70% of all occurrences), 15,660 bytes, 5,376 bytes or 105,856 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs.
The program is not visible. There is no detailed description of this service. Filter.sys is not a Windows system file. The filter.sys file is a file with no information about its developer.
Therefore the technical security rating is 39% dangerous, however you should also read the user reviews.
Recommended: Identify filter.sys related errors
Important: Some malware disguises itself as filter.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the filter.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.
Best practices for resolving filter issues
A clean and tidy computer is the key requirement for avoiding problems with filter. 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 filter.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
farchns.dll remindme.exe 1f0fb7c2d13cc0c07ff2ca40747bc03e_remove360.bat filter.sys xgusb.cpl war_rock_toolbar.dll shadowservice.exe keyboardsurrogate.exe mr2kserv.exe creator-ie-helper.dll trojankiller.exe [all]
Score
User Comments
(further information)
Summary: Average user rating of filter.sys: based on 1 vote with 1 user comment. One user thinks filter.sys is essential for Windows or an installed application.