What Does a Disk Defragmenter Do?

Disk defragmenter is a tool available on the Windows operating system platform that rearranges files contained on the hard drive to reduce program loading and start up times.


When hard drives are full and files are loaded or deleted, they become cluttered because files are saved to different parts of the hard drive's physical disc. This means the hard drive must take more time to access split up or fragmented files.


Disk defragmenting should be part of routine maintenance to keep a hard drive operating at peak efficiency. The application should be run at least once every couple months.

Time Frame

Depending on the amount of data on the hard drive, defragmenting can take less than an hour or much longer. Usually letting the defragmenter run over night is sufficient.


The disc defragmenter does not significantly increase hard drive capacity, because it mainly reorders files. Deleting unwanted programs and files before defragmenting is a good way to free up space and to reduce the time it takes to defragment.

Old Hardware

Old hard drives that have been neglected and ran at near maximum capacity for a long time may experience errors or freezing when attempting to defragment.