What is redbook?

The genuine redbook.sys file is a software component of Digital CD Audio Playback Filter Driver by Microsoft.
An audio filter driver that comes with Windows XP, this driver works with several CD-ROM devices. It allows audio to be played back from your CD player, and includes an audio filter. Windows provides this driver so that you can utilize a CD-ROM that may not have proprietary drivers. Founded in 1975, Microsoft's flagship product is the Windows operating system, which is installed on over 90% of workstations worldwide.

Redbook stands for Redbook Audio Filter Driver

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

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

Redbook.sys file information

The process known as Redbook Audio Filter Driver or Redbook-Audiofiltertreiber or Digital CD Audio Playback Filter Driver belongs to software Digital CD Audio Playback Filter Driver or Filtertreiber für digitale CD-Audiowiedergabe or Microsoft® Windows® Operating System by Microsoft (

Description: The original redbook.sys is an important part of Windows and rarely causes problems. Redbook.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 57,600 bytes (36% of all occurrences), 57,728 bytes, 57,472 bytes, 58,368 bytes or 54,912 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The redbook.sys file is a Windows system file. The program has no visible window. The service has no detailed description. Redbook.sys is a trustworthy file from Microsoft. Therefore the technical security rating is 4% dangerous; however you should also read the user reviews.

Recommended: Identify redbook.sys related errors

Important: Some malware disguises itself as redbook.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the redbook.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 slowly block all my Windows programs I can't start my computer. Important: this file is from windows but it is probable rewrote.
It can be used by a rootkit. It must be exchanged with an uninfected version rather than deleted.
The Redbook system driver (Redbook.sys) is the KS filter that manages the rendering of CD digital audio. The Redbook driver is a client of the SysAudio system driver. The system routes CD digital audio through the file system to the Redbook driver and then to the SysAudio driver. The CD digital audio is rendered on the preferred wave output device (as set in the Multimedia property pages in Control Panel).
  Elena   (further information)
it is a windows system file, however rootkits like to infect it. There may be times when you need to delete the existing one and replace with a new copy to eliminate rootkits and the like.

Rating chart

Summary: Average user rating of redbook.sys: based on 6 votes with 4 user comments. 4 users think redbook.sys is essential for Windows or an installed application. One user thinks it's probably harmless. One user thinks redbook.sys is dangerous and recommends removing it.

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Best practices for resolving redbook issues

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

redbook.sys [all]