How to Scan and Fix Hard Drives with CHKDSK in Windows 10

Microsoft’s hard disk scanning and repair utility, CHKDSK (“check disk”), was introduced over 30 years ago but still has a useful place today.

Users running even the latest Microsoft operating system can still use the command to examine their hard drives for errors and repair them if necessary.

Here’s how to run CHKDSK in Windows 10

  • Click on Start and type cmd in to the Type here to search box, then either right click on Command Prompt and select Run as administrator or just click on Run as administrator on the right

    NOTE: If you cannot see the box, just start typing and it will appear

  • The User Account Control box should appear, click on Yes

  • In the Command Prompt box, type the command below and then press Enter

    chkdsk c: /f /r /x

    If your target drive is an external or non-boot internal disk, the CHKDSK process will begin as soon as we enter the command above.

    If, however, the target drive is a boot disk, the system will ask you if you would like to run the command before the next boot. Type y and restart the computer as soon is convenient and the command will run before the operating system loads, allowing it to gain full access to the disk.

    Example explained

    • c: – The drive letter you want to check
    • /f – Fix any errors it finds
    • /r – Check for bad sectors on the drive

    Additional parameters are available for more specialized tasks, and are detailed at Microsoft’s TechNet site

  • This is the screen you will see if the CHKDSK runs at start up

    A CHKDSK command can take a long time, especially when performed on larger drives HDD drives.

    The scan is normally quite quick on an SSD.

NOTE:  Some users who followed the suggested steps were alarmed to find that their hard drive space was significantly reduced after running the command. This result is due to a failing hard drive, as one of the crucial functions that CHKDSK performs is to identify and block bad sectors on the drive. A few bad sectors on an old drive will typically go unnoticed to the user, but if the drive is failing or has serious problems, you could have huge numbers of bad sectors that, when mapped and blocked by CHKDSK, appear to “steal” significant portions of your hard drive’s capacity.

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