File Version : 5.1.2600.2180 (xpsp_sp2_rtm.040803-2158)
Description : Redbook Audio Filter Driver
Copyright : (C) Microsoft Corporation. All rights reserved.
Product Version : 5.1.2600.2180
Product Name : Microsoft(R) Windows(R) Operating System
Company Name : Microsoft Corporation
Internal Name : redbook.sys
File Size: 54784 byte(s) 53.512 KB
MD5 : f720de7bfe7ae26846e7ebe9caf3f49a
How to Install ql40xx.sys
Repair Sys ProblemsFixing a corrupted or missing ql40xx.sys error is an easy process with a few steps. Open the zip-file you downloaded.Extract the .sys file to a location on your computer. We recommend you to unzip the file to the directory of the program that is requesting the file.
If that doesn't work, you will have to extract the file to your system directory.
By default, this is C:/WINNT/system32/drivers (Windows NT/2000).
or C:/Windows/system32/drivers (Windows XP, Vista, 7).
Make sure overwrite any existing files (but make a backup copy of the original file)
That should be it. Although not necessary you can reboot your computer as well.