O&O Defrag reorganizes files on Windows volumes and can target a whole drive. Windows Explorer can also send one folder or one individual file to O&O Defrag. Its methods do more than join fragmented extents: some place files into defined disk zones according to how the system uses them. O&O Defrag changes physical file placement and does not repair a file system that Windows already reports as damaged.
The Start button has one default method
The main Start action runs OPTIMIZE. Its attached menu selects another method. Holding Ctrl groups several selected drives into one run. Windows Explorer starts a narrower operation: its Defragment context command sends the chosen file or folder to O&O Defrag.
Quick placement and complete reorganization move different amounts
OPTIMIZE/Quick moves misplaced files into their assigned zones without analyzing the entire file system first. O&O describes it for low disk usage. OPTIMIZE/Complete performs a full reorganization and can apply SPACE or COMPLETE behavior to each zone.
A complete pass can take hours, especially on the first run. O&O Defrag may move files that are not fragmented because the selected layout places them elsewhere.
Zone filing starts disabled
Settings > O&O Defrag > File into zones turns zone filing on. The default layout keeps operating-system and program data apart from user data. It sends seldom-used or very large files to the last zone. A file larger than five hundred megabytes enters the third zone under that default definition.
The zone rule classifies placement; it does not change a large file’s contents or split the file into smaller documents. OPTIMIZE/Quick can move a misplaced file to its assigned zone, while OPTIMIZE/Complete can rebuild the broader layout.
SSD work needs the SOLID methods
O&O warns against applying speed-zone filing intended for hard disks to an SSD. Its documentation points SSD work to the SOLID methods instead. Copying an HDD placement plan to an SSD therefore ignores the storage-specific path that the publisher documents.
Quick placement aims at a smaller amount of disk work. Complete reorganization can move much more data because it rebuilds the selected layout.
A file-system error stops the operation
O&O Defrag refuses to defragment a volume when Windows chkdsk reports a file-system problem. The user must repair the volume with Windows disk checking before defragmentation can continue.
Automatic work excludes removable drives
Automatic defragmentation watches write activity and newly added files. After the user stops accessing a newly fragmented file, O&O Defrag can work on it in the background. A separate regular pass covers the remaining files. External USB and FireWire drives stay outside this automatic path because either connection can disappear during the operation.
A schedule can stop and resume later
A scheduled job can set a maximum running time. O&O Defrag stops an unfinished pass at that limit and continues it at the next run. If the computer is off at the scheduled start, the job is normally skipped. The separate start-later option changes that missed-start behavior.
