Repair and Download cdosys.dll Now

Sometimes Windows system displays error messages regarding corrupted or missing cdosys.dll 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 cdosys.dll file can therefore effect in failed execution of the started process.

cdosys.dll file Microsoft CDO for Windows Library. The file was developed by for use with software. Here you will find detailed information about the file and instructions how to proceed in the event of cdosys.dll related errors on your device. You can also download cdosys.dll file compatible with Windows 10, Windows 8.1, Windows 8, Windows 7, Windows 7, Windows Vista, Windows Vista, Windows XP devices which will (most probably) allow you to solve the problem.

For Windows Compatible with: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows 7, Windows Vista, Windows Vista, Windows XP

File info

General information
Filename cdosys.dll
File extension DLL
Description Microsoft CDO for Windows Library
Program Microsoft® Windows® Operating System
Author Microsoft Corporation
MIME type application/octet-stream
File type Dynamic link library
System Windows NT 32-bit
Copyrights © Microsoft Corporation. All rights reserved.
Character set Unicode
Language cod English (U.S.)

There are various types of errors related to cdosys.dll file. cdosys.dll 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 cdosys.dll file. If you encounter one listed below (or similar), please consider the following suggestions.

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



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


Problems related to cdosys.dll 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 cdosys.dll 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.

cdosys.dll 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 cdosys.dll 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 cdosys.dll 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 cdosys.dll 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 cdosys.dll file. After an error related to%fileextension% file has been discovered, the program attempts to automatically replace the cdosys.dll 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 cdosys.dll 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 cdosys.dll 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 cdosys.dll file

The last solution is to manually download and replace cdosys.dll 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 cdosys.dll file.

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

  • Windows 10: C:\Windows\System32\
  • Windows 8.1: C:\Windows\System32\
  • Windows 8: 1: C:\Windows\System32\
  • Windows 7: C:\Windows\System32\
  • Windows 7: C:\Windows\System32\
  • Windows Vista: ---
  • Windows Vista: ---
  • Windows XP: ---

If the steps did not solve your cdosys.dll 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 cdosys.dll
System Windows 10
File size 830464 bytes
Date 2017-03-18
File details
MD5 3d71476996ae4a58c624c68d02940611
SHA1 b8b5532a315de786738d9e99568e864f38b13dfe
SHA256 a99abe131da7ad6130e4d79cecb05892d33240ac8c8f417224f6bee5dd543686
CRC32 53c23529
Example file location C:\Windows\System32\
Filename cdosys.dll
System Windows 8.1
File size 854528 bytes
Date 2014-11-21
File details
MD5 3b4d1f6f5c8e042324a6ec70b53d3cdc
SHA1 39345a011ba1878a459c13caaa1065f3228ef6da
SHA256 deced8e0adcee1b689c8d7553fb18e0601ac48e3e43c13b970551c047af4fe9b
CRC32 7cc932de
Example file location C:\Windows\System32\
Filename cdosys.dll
System Windows 8
File size 818688 bytes
Date 2012-07-26
File details
MD5 1fa8bbc90105625e9eb4ef90ed255af6
SHA1 b4d70bb868dd8c7c29a481e6e10082b37ec5369b
SHA256 8a0155c5e828efc9b7f00ec36cf74c36532eb2dde749c997acd08a02cf00f9d7
CRC32 ae86db32
Example file location 1: C:\Windows\System32\
Filename cdosys.dll
System Windows 7
File size 1133568 bytes
Date 2010-11-21
File details
MD5 82c87fbf43957e69530eb6521f8ff0d1
SHA1 07c62f5bf6e710b7000c9a427f8569d42cd24083
SHA256 e27e944f706763ada042501aca3d11101bd3f4407d6977d200abd313feebe053
CRC32 11db258e
Example file location C:\Windows\System32\
Filename cdosys.dll
System Windows 7
File size 805376 bytes
Date -0001-11-30
File details
MD5 98c66b8010cd7b6865f308abd87c8e86
SHA1 1e477f65a1dc363b3dfcb6c061fdd0185d5e4c59
SHA256 ac3ace9479d3e52e25afb361e0e9b8e538a1faefbf7da93c6b68b6c24a3661d0
CRC32 3784e8c6
Example file location C:\Windows\System32\
Filename cdosys.dll
System Windows Vista
File size 805888 bytes
Date -0001-11-30
File details
MD5 cda90f015b5edef9463a672b7c10654e
SHA1 f4d8bee189aa0b95c9f48a8a1820cb8f4b209b65
SHA256 58a2110b06228edac9f80c15584fccd008faf0a5871569f5d081a8210c00fb30
CRC32 6eef9fb2
Example file location ---
Filename cdosys.dll
System Windows Vista
File size 1151488 bytes
Date 2008-01-21
File details
MD5 d724b9304f90f10e9fb2501d1f0eebf5
SHA1 d462409f51b58f72f7824ff166ce50ab49b45284
SHA256 65ba066f9f633c1974e2441bf0dbbd0c4a3495c75794aeb406992c83223dd485
CRC32 1cdac55a
Example file location ---
Filename cdosys.dll
System Windows XP
File size 2091520 bytes
Date 2008-04-14
File details
MD5 465f0eb786e0f667e4374704836b5717
SHA1 708de572a8d0be3d00aa579e2eea611156fc7b5d
SHA256 b0bbc946df00814001872b7d536c21c06945ac653460f79b6f68d6917bfd1568
CRC32 80450d40
Example file location ---