What is mouclass?

Mouclass.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 mouclass.sys is a Windows system file or if it belongs to an application that you can trust.

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

Mouclass.sys file information

The process known as Mouse Class Driver or Mausklassentreiber or Pilote de la classe Souris belongs to software Microsoft Windows Operating System or Betriebssystem Microsoft Windows or Système d’exploitation Microsoft Windows by Microsoft (

Description: Mouclass.sys is an important part of Windows, but often causes problems. The mouclass.sys file is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 23,040 bytes (83% of all occurrences) or 41,552 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. Mouclass.sys is a Windows core system file. The program is not visible. There is no detailed description of this service. Mouclass.sys is a Microsoft signed file. mouclass.sys appears to be a compressed file. Therefore the technical security rating is 0% dangerous, however you should also read the user reviews.

Recommended: Identify mouclass.sys related errors

Important: Some malware disguises itself as mouclass.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the mouclass.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.


User Comments

Mine became infected, but once cleaned worked perfectly for mouse function
mouclass.sys is a virus particuarly a stealth trojan that operates in your operating system ROOTKIT use combofix to fix it
  Windows Defender  
My AVG virus scan shows it to be a virus but does not heal it
mouclass.sys is the system IRP (I/O request packet) for the mouse class driver. It is the "on/off" switch in boot up for your mouse. Meaning if you delete this.sys on your computer your mouse will have trouble working. There are viruses built to attack this file in the registry, however the file itself is not a virus.
I got error "File mouclass.sys is corrupt or unreadable" but was able to fix it running XP Repair Install - and checking my drive integrity.
Not to much I ran the DLL File Finder think it said I was missing this file
  phillip hower jr  

Rating chart

Summary: Average user rating of mouclass.sys: based on 8 votes with 6 user comments. One user thinks mouclass.sys is essential for Windows or an installed application. 3 users think it's probably harmless. 3 users suspect danger. One user thinks mouclass.sys is dangerous and recommends removing it. One user is not sure about it.

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Best practices for resolving mouclass issues

A clean and tidy computer is the key requirement for avoiding problems with mouclass. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic 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 6resmon 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 7DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the mouclass.sys process on your computer, the following programs have proven to be helpful: ASecurity 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. BMalwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

mouclass.sys [all]