What is Cdfs?

The genuine Cdfs.sys file is a software component of Microsoft Windows Operating System by Microsoft.
A general driver, this file allows your Windows Operating System to interface with the file system read off of the disc in your CD-ROM. This file has been included in all releases of Windows since Windows 98. Founded in 1975, Microsoft's flagship product is the Windows operating system, which is installed on over 90% of workstations worldwide.

CDFS stands for CD-ROM File System Driver

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

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

Cdfs.sys file information

The process known as CD-ROM File System Driver belongs to software Microsoft Windows Operating System by Microsoft (

Description: Cdfs.sys is an important part of Windows, but often causes problems. The Cdfs.sys file is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 63,744 bytes (93% of all occurrences) or 70,144 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. It is a Windows core system file. The program has no visible window. The service has no detailed description. The Cdfs.sys file is a trustworthy file from Microsoft. Cdfs.sys appears to be a compressed file. Therefore the technical security rating is 3% dangerous, however you should also read the user reviews.

Recommended: Identify Cdfs.sys related errors

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

It's Microsoft Windows CD-ROM file system system driver file.

Summary: Average user rating of Cdfs.sys: based on 2 votes with 1 user comment. One user thinks Cdfs.sys is essential for Windows or an installed application. One user suspects danger.

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Best practices for resolving Cdfs issues

A clean and tidy computer is the key requirement for avoiding problems with Cdfs. 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 Cdfs.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

Cdfs.sys [all]