How to Repair qos.CHM? Download Now

Sometimes Windows system displays error messages regarding corrupted or missing qos.CHM files. Situations like that can occur, for example, during a software installation process. Each software program requires certain resources, libraries, and source data to work properly. Corrupted or nonexistent qos.CHM file can therefore effect in failed execution of the started process.

qos.CHM file Compiled HTML Help. The file was developed by Microsoft for use with Windows software. Here you will find detailed information about the file and instructions how to proceed in the event of qos.CHM related errors on your device. You can also download qos.CHM file compatible with Windows 8, Windows 7, Windows Vista devices which will (most probably) allow you to solve the problem.

For Windows Compatible with: Windows 8, Windows 7, Windows Vista

File info

General information
Filename qos.CHM
File extension CHM
Type Compiled HTML Help
Description Compiled HTML Help
Program Windows 8
Software Windows
Author Microsoft
Software version 8
MIME type application/x-chm
Language cod English (U.S.)

There are various types of errors related to qos.CHM file. qos.CHM file may be located in wrong file directory on your device, may not be present in the system, or may be infected with malicious software and therefore not work correctly. Below is a list of most common error messages related to qos.CHM file. If you encounter one listed below (or similar), please consider the following suggestions.

  • qos.CHM is corrupted
  • qos.CHM cannot be located
  • Runtime Error - qos.CHM
  • qos.CHM file error
  • qos.CHM file cannot be loaded. Module was not found
  • cannot register qos.CHM file:
  • qos.CHM file could not be loaded
  • qos.CHM file doesn't exist



Application could not be started because qos.CHM file is missing. Reinstall the application to solve the problem.


Problems related to qos.CHM can be addressed in various ways. Some methods are meant only for advanced users. If you don't have confidence in your skills, we suggest consulting a specialist. Fixing qos.CHM file errors should be approached with utmost caution for any mistakes can result in unstable or unproperly working system. If you have the necassary skills, please proceed.

qos.CHM file errors can be caused by various factors, so its is beneficial to try to fix them using various methods.

Step 1: Scan your computer for any malicious software

Virus Scan

Windows files are commonly attacked by malicious software that prevents them from working properly. First step in addressing problems with qos.CHM file or any other Windows system files should be scanning the system for malicious software using an antivirus tool.

If by any chance you don't have any antivirus software installed on your system yet, you should do it immediately. Unprotected system is not only a source of file errors, but, more importantly, makes your system vulnerable to many dangers. If you don't know which antivirus tool to choose, consult this Wikipedia article – comparison of antivirus software.

Step 2: Update your system and drivers.

Windows Update

Installing relevant Microsoft Windows patches and updates may solve your problems related to qos.CHM file. Use dedicated Windows tool to perform the update.

  1. Go to the Windows "Start" menu
  2. Type "Windows Update" in the search field
  3. Choose the appropriate software program (name may vary depending on your system version)
  4. Check if your system is up to date. If any unapplied updates are listed, install them immediately.
  5. After the update has been done,restart your computer in order to complete the process.

Beside updating the system, it is recommended that you install latest device drivers, as drivers can influence proper working of qos.CHM or other system files. In order to do so, go to your computer or device producer's website where you will find information regarding latest driver updates.

Step 3: Use System File Checker (SFC) tool

System File Checker

System File Checker is a Microsoft Windows tool. As the name suggests, the tool is used for identyfing and addressing system file related errors, including those related to qos.CHM file. After an error related to%fileextension% file has been discovered, the program attempts to automatically replace the qos.CHM file with properly working version. To use the tool:

  1. Go to the Windows "Start" menu
  2. Type "cmd" in the search field
  3. Locate "Command Prompt" result – don't run it yet:
  4. Click the right mouse button and select "Run as Administrator" option
  5. Type "sfc /scannow" in console prompt to start the program and follow the instructions

Step 4: Restoring Windows system

Windows Recovery

Another approach is to restore system to previous state, before the qos.CHM file error occured. In order to restore your system, follow the instructions below

  1. Go to the Windows "Start" menu
  2. Type "System Restore" in the search field
  3. Start the system restore tool – it's name may differ depending on version of the system
  4. The application will guide you through the process – read the messages carefully
  5. After the process has finished, restart your computer.

If all the above-mentioned methods failed and the qos.CHM file problem has not been resolved, proceed to the next step. Remember that the following steps are intended only for advanced users.

Download and replace qos.CHM file

The last solution is to manually download and replace qos.CHM file in appropriate folder on the disk. Select file version compatible with your operating system and click the "Download" button. Next, go to your web browser's "Downloaded" folder and copy the downloaded qos.CHM file.

Go to the folder where the file should be located and paste the downloaded file. Below is the list of qos.CHM file example directory paths.

  • Windows 8: C:\Windows\Help\mui\0409\
  • Windows 7: C:\Windows\Help\mui\0409\
  • Windows Vista: C:\Windows\Help\mui\0409\

If the steps did not solve your qos.CHM file problem, you should consult a professional. A probability exists that the error(s) might be device-related and therefore should be resolved at the hardware level. A fresh operating system installation might be necessary – a faulty system installation process can result in data loss.

File versions list

Filename qos.CHM
System Windows 8
File size 28923 bytes
Date 2012-07-26
File details
MD5 0f1a06a1ab10efd9bc8edcc39814ba02
SHA1 b75abbb7030f3a320277027078f4be5fd33ace0d
SHA256 3a8e7d5cfbb1bd4c6b409019f5676612a83a2889fe4e165e1c24a33345ef7e80
CRC32 8a617642
Example file location C:\Windows\Help\mui\0409\
Filename qos.CHM
System Windows 7
File size 30083 bytes
Date -0001-11-30
File details
MD5 e6c1cc87b0d2390262e35ec52ec0bdbe
SHA1 51ecf2890e9edd98c00dd5635e83f4a4a54ac14e
SHA256 3bfcd5ea3a1f962e1d73b778ae58851e757505fe5342fe40a88664d924a4ce4a
CRC32 952395fa
Example file location C:\Windows\Help\mui\0409\
Filename qos.CHM
System Windows Vista
File size 26971 bytes
Date -0001-11-30
File details
MD5 6f87ee931746ee3645878f73b0dd0adf
SHA1 3d1d147838c14b6ff71e488c3c8b8080b14a360f
SHA256 55cbf6eaf5e007e6dd2f703abf3663e1e892fc487a9ac8dd2b65450bf7ac5cf2
CRC32 d4f8862d
Example file location C:\Windows\Help\mui\0409\