Free defragmentation software

UltraDefrag is a disk defragmentation utility for Microsoft Windows. Prior to version 8.0.0 it was released under the GNU General Public License.

JkDefrag is a free open-source disk defragmenting utility computer program for Windows. It was developed by Jeroen Kessels (initials "JK", hence the name) beginning in 2004 and was released under the GNU General Public License. Since version 4 of 2008, much changed from previous versions, JkDefrag was renamed MyDefrag by its developer; earlier JkDefrag versions continued to be available. MyDefrag, which was closed source freeware, was discontinued, with the last version being v4.3.1, file date 21 May 2010; for several years the MyDefrag website has been a redirect to the still-existing JkDefra