UltraDefrag is an open source disk defragmenter for Windows NT 4.0 and later operating systems. It makes use of the same defragmenting API used by many other windows defrag utilities, both open and closed source. However, UltraDefrag has many features that makes it unique. Firstly it has a kernel mode driver that does most of the work, secondly is the ability to run the application at boot up time in a manner similar to chkdsk. This allows for faster defragmentation time and the ability to defragment all files including system files. It can also defrag single file or multiple directory and can generate a list of all fragmented files. The program is available for both 32bit and 64bit version of Windows running on both AMD and Intel based processor.

UltraDefrag has the following features:

        * Defragmentation algorithm was completely rewritten to be more effective. Click <Here>To know more about the algorithm. Now UD is more reliable and effective.
        * GUI configurator option to allow UD to be configured using a graphical window.
        * Very fast defragmentation, the work is done via a kernel mode driver which has an optimal defraging algorithm.
        * Single file or directory defragmentation ability. Select any file or folder in Explorer and choose the appropriate context menu item to defragment them.
        * Debug logging feature - Program writes debugging information to %windir%\UltraDefrag\logs directory. That means if your windows is installed in drive 'C' and directory name is 'Windows', then logs can be found in C:/Windows/UltraDefrag/Logs.
        * Very small engine written in pure C.
        * PortableDefrag can be installed on demand which can be carried around in USB storage devices and used without any installation.
        * Nice graphical interface - compact and functional.
        * A new graphical configurator which allows access to help files, boot time defrag option and UD font settings.
        * Safety, because the file moving is accomplished with Microsofts own Defrag API.
        * Simple to use.
        * Set programs filter to exclude unwanted files and folders from the analysis.
        * Ability to generate html reports of fragmentation status.
        * Ability to include/exclude files based on simple filters.
        * Native x64 support.
        * Free: Distributed with full source code under the GNU General Public License.
        * Many GUI translations were made:

        Catalan, Chinese (Simplified), Chinese (Traditional), Japanese, Dutch, Danish, French, Farsi, German, Greek, Italian, Portuguese, Slovak, Swedish, Slovenian, Czech, Korean, Latvian, Polish, Portuguese (Brazilian), Spanish (AR).

        * Scripting support for boot time interface. Now you can do anything with your drives during the Windows Boot Process.
        * Portable Version also available.
        * Complete documentation avalable both online and on the installer.