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Description of the New Command Line Defrag.exe Included with Windows XP

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This article was previously published under Q283080
This article describes the Defrag.exe command line utility that is included with Windows XP. The Defrag.exe command line utility is specifically designed for scripting and for use by system administrators. To defragment a volume using Windows, follow these steps:
  1. Right-click My Computer, and then click Open.
  2. Right-click the volume that you want to defragment, and then click Properties.
  3. Click the Tools tab, and then click Defragment Now.
  4. Click Defragment.
  5. Click View Report to view the Defragmentation Report, which displays detailed information about the volume that you defragmented.
For additional information about the limitations of the Disk Defragmenter tool in Windows, click the following article number to view the article in the Microsoft Knowledge Base:
314848 How to Defragment Your Disk Drive Volumes in Windows XP
The Defrag.exe command line utility locates and consolidates fragmented boot files, data files, and folders on local volumes.

When you are saving files, the file is not necessarily saved as an entire file or folder in a contiguous space. The files are saved in the first available space on a volume. After a large portion of the volume has been used for file and folder storage, most of the new files are saved in pieces across the volume. When you delete files or folders, the empty spaces left behind fill in randomly as you store new ones.

You can find the Defrag utility, Defrag.exe, in the %SystemRoot%\System32 folder. You can defragment disk volumes formatted as FAT, FAT32, and NTFS. Defrag also works with Dynamic as well as Basic Disks.

Command Line Parameters and Explanations


defrag volume [-a] [-f][-v] [-?]


The drive letter or a mount point of the volume to be defragmented

Analyze only

Forces defragmentation of the volume regardless of whether it needs to be defragmented or even if free space is low

Verbose output

Display the help text

Note: The volume must have at least 15 percent free space for Defrag to completely and adequately defragment it. Defrag uses this space as a sorting area for file fragments. If a volume has less than 15 percent free space, Defrag only partially defragments it.

To interrupt the defragmentation process, at the command line, press CTRL+C.

Article ID: 283080 - Last Review: 01/27/2006 01:48:59 - Revision: 2.4

  • Microsoft Windows XP Home Edition
  • Microsoft Windows XP Professional
  • kbenv kbinfo KB283080