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Auslogics Disk Defrag vs O&O Defrag: catalog facts
Auslogics Disk Defrag	O&O Defrag
Free Disk Defrag is free; the separate Disk Defrag Ultimate edition is paid.	Paid Commercial software sold by O&O Software.
Windows	Windows
Free alternative to the built-in Windows defragmenter From a long-running Windows utilities developer	Optimizes drives automatically in the background Maintained by an established Windows software vendor
Windows only Defragmenting brings little benefit on SSDs	Windows only Paid software
Downloadable app	Downloadable app
Closed source	Closed source
License not stated	License not stated
No account needed	Not stated if an account is needed
Works offline	Works offline
Official website Full listing and sources Checked October 1, 2026	Official website Full listing and sources Checked September 24, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.