CDO.DLL Informations - Download and Fix

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

CDO.DLL file Collaboration Data Objects 1.21s for Windows NT. 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 CDO.DLL related errors on your device. You can also download CDO.DLL file compatible with Windows XP, Windows XP devices which will (most probably) allow you to solve the problem.

For Windows Compatible with: Windows XP, Windows XP

File info

General information
Filename CDO.DLL
File extension DLL
Description Collaboration Data Objects 1.21s for Windows NT
Program Microsoft Exchange
Author Microsoft Corporation
MIME type application/octet-stream
File type Dynamic link library
System Windows NT 32-bit
Copyrights Copyright (C) 1986-2003 Microsoft Corp. All rights reserved.
Character set Windows, Latin1
Language cod English (U.S.)

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

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



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


Problems related to CDO.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 CDO.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.

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

The last solution is to manually download and replace CDO.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 CDO.DLL file.

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

  • Windows XP: C:\Program Files\Common Files\System\MSMAPI\1033\
  • Windows XP: C:\Program Files\Common Files\System\MSMAPI\1033\

If the steps did not solve your CDO.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 CDO.DLL
System Windows XP
File size 733752 bytes
Date 2017-05-10
File details
MD5 394ad5d3570c3bd3a27ebaa63b9d5795
SHA1 e529063db4d12fc1ef7fca533301acf6af8b1559
SHA256 01f55e6a41e01539496dad9f7332e14ccf3ca9c24cc06003a6e2be607f78b6f7
CRC32 3ee79618
Example file location C:\Program Files\Common Files\System\MSMAPI\1033\
Filename CDO.DLL
System Windows XP
File size 810256 bytes
Date 2017-05-10
File details
MD5 577abfa927c60e2379e61812cb6db167
SHA1 29f4a14226f39bc0f57be6dad8e8af23acbd5cfc
SHA256 b01c4b7f3d87012f6b59bbeb65aefa685322dc126f4d3a8f532448f6c574e747
CRC32 0fb4114a
Example file location C:\Program Files\Common Files\System\MSMAPI\1033\