Troubleshoot defragsvc.dll Errors and Download File

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

defragsvc.dll file Microsoft\Drive Optimizer. 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 defragsvc.dll related errors on your device. You can also download defragsvc.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 defragsvc.dll
File extension DLL
Description Microsoft\Drive Optimizer
Program Microsoft® Windows® Operating System
Author Microsoft Corporation
MIME type application/octet-stream
File type Executable application
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 defragsvc.dll file. defragsvc.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 defragsvc.dll file. If you encounter one listed below (or similar), please consider the following suggestions.

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



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


Problems related to defragsvc.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 defragsvc.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.

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

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

Go to the folder where the file should be located and paste the downloaded file. Below is the list of defragsvc.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 defragsvc.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 defragsvc.dll
System Windows 10
File size 395776 bytes
Date 2017-03-18
File details
MD5 6fdd4ff232446d9b255e1ea83751ae01
SHA1 59d57447672102aff73a17f290ff40aaf3dab6f7
SHA256 bebccf3c2846463d27c1bca8def61d79dfcc342b9ccbaf983fa4b7be7a6e386a
CRC32 fefb09dc
Example file location C:\Windows\System32\
Filename defragsvc.dll
System Windows 8.1
File size 418816 bytes
Date 2014-11-21
File details
MD5 7ee8e5122bdc8b3057b0ad65c13a776e
SHA1 d655d3498ffde026ab3c2254f15f9de2a8744fcc
SHA256 430cb3a551fc7c64bdf04b93dd249948f22e9f43941c8e2f72bfd94fe37466f5
CRC32 c59929f0
Example file location C:\Windows\System32\
Filename defragsvc.dll
System Windows 8
File size 273920 bytes
Date 2012-07-26
File details
MD5 3d36fbe5abaf0d531085c5d3381dc770
SHA1 a66a8d6ab77631daad7e7fc7de32ed1b22391760
SHA256 87faf495f6403eaa3728c6d100a7a87a6d9ae2376e29d654b6beda4394f08090
CRC32 462fc8bc
Example file location 1: C:\Windows\System32\
Filename defragsvc.dll
System Windows 7
File size 291328 bytes
Date 2009-07-14
File details
MD5 3cec7631a84943677aa8fa8ee5b6b43d
SHA1 1a0f76793cd258b05224a94e7ee2143a9dcb8506
SHA256 32061dac9ed6c1eba3b367b18d0e965aeec2df635dcf794ec39d086d32503ac5
CRC32 01909ad7
Example file location C:\Windows\System32\