defragproxy.dll - How to Fix? Download Now

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

defragproxy.dll file Microsoft® Drive Optimizer Proxy 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 defragproxy.dll related errors on your device. You can also download defragproxy.dll file compatible with Windows 10, Windows 8.1, Windows 8, Windows 7 devices which will (most probably) allow you to solve the problem.

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

File info

General information
Filename defragproxy.dll
File extension DLL
Description Microsoft® Drive Optimizer Proxy 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 defragproxy.dll file. defragproxy.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 defragproxy.dll file. If you encounter one listed below (or similar), please consider the following suggestions.

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



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


Problems related to defragproxy.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 defragproxy.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.

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

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

Go to the folder where the file should be located and paste the downloaded file. Below is the list of defragproxy.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\

If the steps did not solve your defragproxy.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 defragproxy.dll
System Windows 10
File size 14336 bytes
Date 2017-03-18
File details
MD5 e54ef8949c3f20dbf59af6d623440fe7
SHA1 a4845231a78e321119db9701603861d8dad0af9a
SHA256 a658ee737a7f8e626709cc8b235ca75d399af0685708cf62117b7208719c2840
CRC32 7e56a25f
Example file location C:\Windows\System32\
Filename defragproxy.dll
System Windows 8.1
File size 13824 bytes
Date 2014-11-21
File details
MD5 85e0aaaa48cbd4757ddc1c8cd0bfef42
SHA1 451cbf4ad165d43899aa1355b3b356fb7dc20add
SHA256 e2e80e0a726ec7a6bcaa8b40f978a6495db70b9c7478389ea047e29b37234732
CRC32 733c6dbb
Example file location C:\Windows\System32\
Filename defragproxy.dll
System Windows 8
File size 11776 bytes
Date 2012-07-26
File details
MD5 7d94321a010b255b9f573f86b48693bb
SHA1 412cc02ae0f52daa023f273b42d0dc5465d5ab97
SHA256 db6ff501179849743a70c19a987568e9fbbd05b436461d3be1fd97eb450ba0f2
CRC32 c3742ecb
Example file location 1: C:\Windows\System32\
Filename defragproxy.dll
System Windows 7
File size 16384 bytes
Date 2009-07-14
File details
MD5 97b73caed88d1d8021a8ca3f2605ef6a
SHA1 1ff43257e8dbfb3657bc198d62a0cf3a4ce8267c
SHA256 faa6078b76fb2b64b4fd9a4789466a61894f226745d5b9f90432692bfe9bae90
CRC32 23ae94c6
Example file location C:\Windows\System32\