| O&O Defrag | |
|---|---|
| | |
| O&O Defrag 14 Professional Edition running under Windows 7 | |
| Developers | O&O Software |
| Stable release | 30.5.1211 / December 12, 2025 |
| Operating system | Windows NT 4.0 to Windows 11 |
| Type | Defragmentation |
| License | Shareware |
| Website | oo-software |
O&O Defrag is a Windows defragmentation utility sold by German software developer O&O Software. It has won several awards [1] by PC journals and magazines, and is certified by Microsoft [ citation needed ] for all its current NTFS-based operating systems, including NT 4.0, 2000, XP, Vista, 7, 8, 8.1, 10, 11, Server 2003, 2008, 2008 R2, 2012, 2012 R2, 2016, 2019, 2022 and 2025.
There are five different defrag methods: Stealth, Space, Complete/Name, Complete/Modified, Complete/Access. "Stealth" is designed for use on PCs with large files and little free space, while the "Space" method is designed for heavily fragmented drives. The three "Complete" methods (Name, Modified and Access) sort the files on your drives alphabetically, according to date last changed, and according to date last accessed.