Defrag Options & Command line switches in Windows 10/8/7

The Disk Defragmenter in Windows 10/8/7 offers some additional options compared to that in Windows Vista. Its command line version has some additional switches. Open an elevated command prompt windows.

Defrag Command line switches

Type Defrag /? and hit Enter. This will show you all the defragmentation options and command line switches.

cmd defrag

Here is the list of Defrag switches:

Value   Description

/A      Perform analysis on the specified volumes.

/C      Perform the operation on all volumes.

/D      Perform traditional defrag (this is the default).

/E      Perform the operation on all volumes except those specified.

/H      Run the operation at normal priority (default is low).

/K      Perform slab consolidation on the specified volumes.

/L      Perform retrim on the specified volumes.

/M      Run the operation on each volume in parallel in the background.

/O      Perform the proper optimization for each media type.

/T      Track an operation already in progress on the specified volume.

/U      Print the progress of the operation on the screen.

/V      Print verbose output containing the fragmentation statistics.

/X      Perform free space consolidation on the specified volumes.

So, if you open cmd and type in “defrag /C /H /M” it will run defrag on all volumes, at a higher priority, in parallel.

You might also want to check out some of the best free defragmentation software for Windows.

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Anand Khanse is the Admin of, a 10-year Microsoft MVP Awardee in Windows (2006-16) & a Windows Insider MVP. Please read the entire post & the comments first, create a System Restore Point before making any changes to your system & be careful about any 3rd-party offers while installing freeware.