UltraDefrag is a
disk defragmentation utility for
Microsoft Windows. Prior to version 8.0.0 it was released under the
GNU
GNU () is an extensive collection of free software
Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any ...
General Public License
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general us ...
. The only other Windows-based defragmentation utility licensed under the GNU GPL was
JkDefrag
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 o ...
, discontinued in 2008.
In 2018, UltraDefrag sources have been relicensed to Green Gate Systems. Their enhanced version, released under a