What is Defrag.exe?

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the Defrag.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

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Defrag.exe file information

Windows Task Manager with Defrag
Defrag.exe process in Windows Task Manager

The process known as Disk Defragmenter Module belongs to software Windows Disk Defragmenter or Windows-Laufwerksoptimierung by Microsoft ( or Microsoft Corp. and Executive Software International (

Description: The original Defrag.exe is an important part of Windows and rarely causes problems. The file Defrag.exe is located in the C:\Windows\System32 folder. Known file sizes on Windows 10/8/7/XP are 180,736 bytes (50% of all occurrences) or 25,088 bytes. 
Defrag.exe is a Windows core system file. The program is not visible. The Defrag.exe file is a Microsoft signed file. Therefore the technical security rating is 4% dangerous, however you should also read the user reviews.

Recommended: Identify Defrag.exe related errors

If Defrag.exe is located in a subfolder of the user's profile folder, the security rating is 56% dangerous. The file size is 133,632 bytes. There is no information about the author of the file. The program is not visible. It is not a Windows core file.

Important: Some malware camouflages itself as Defrag.exe, for example WS.Reputation.1 (detected by Symantec), and Artemis!D486FEE61A5D (detected by McAfee). Therefore, you should check the Defrag.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

Defrag.exe is command line utility locates and consolidates fragmented boot files, data files, and folders on local volumes.
  Heidi   (further information)
this is a program located under C:\Program Files

Summary: Average user rating of Defrag.exe: based on 2 votes with 2 user comments. 2 users think Defrag.exe is essential for Windows or an installed application. One user is not sure about it.

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Best practices for resolving Defrag issues

A clean and tidy computer is the key requirement for avoiding problems with Defrag. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the Defrag.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

Defrag.exe [all]