Use a New Command in Windows 8.1 to Find out how Your Disk Space is Being Used


If you would really like to find out the details of what is using space on your hard drive, Windows 8.1 has a new tool that will give you as much detail as you are likely to want. The command line in Windows 8.1 has added a powerful new space reporting function to the File System Utility command Fsutil. This feature is not available in older versions of Windows.

Fsutil is a Windows command-line suite with an assortment of sub-commands for managing the file system. In Windows 8.1, the new sub-command that has been added will reveal information such as how much space is being used by hidden metadata files. Statistics about some of these such as the Master File Table (MFT) are normally not obvious. The new sub-command also gives a count of both the number of hidden system files and how many user files and folders there are as well as other information.

Fsutil applies to NTFS file structures and has to be run with administrative privileges. To generate a report of space usage, right-click the Windows 8.1 flag icon in the lower left corner of the desktop and select Command Prompt (Admin). Then enter

    fsutil volume allocationreport X:

Here X: stands for whatever volume or drive you are interested in. Creating the report takes a minute or two. Since there is a lot of information, it is probably better to send the report to a text file rather than to display it on the screen. You can designate the text file to be placed in any location you like. Then the command might be something like

     fsutil volume allocationreport X: >somefolder\allocation.txt

where “somefolder” is a complete folder path of your choice including the drive. If there are spaces in the file or folder name, the complete file and pathname will have to be enclosed in quotes.

Additional description of the information provided by this new sub-command and how to use it can be found at this MSDN article.

Fsutil is for advanced management of NTFS systems and isn’t something you use every day but this function is new in Windows 8.1 so I thought I’d pass it along for more experienced PC users.

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This tips section is maintained by Vic Laurie. Vic runs several websites with Windows how-to's, guides, and tutorials, including a site for learning about Windows and the Internet and another with Windows 7 tips.

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It was almost instantaneous on my Sam 840EVO SSD. 64 bit.