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How to Scan & Fix Hard Drives with CHKDSK in Windows 8

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 8.

CHKDSK Windows 8

First, launch the Start Screen by pressing the Windows key or clicking the lower left corner of the Taskbar. From the Start Screen, search for the Windows Command Prompt by typing “cmd”. Right-click on the Command Prompt and choose “Run as Administrator” from the bar at the bottom of the screen.

CHKDSK Windows 8

After authenticating as an administrative user, you’ll be at the Windows Command Prompt, a familiar interface for users who remember the days before Windows NT. Type the command “chkdsk” followed by a space, then the letter of the drive you wish to examine or repair. In our case, it’s external drive “L.”

Simply running the CHKDSK command will only display the disk’s status, and won’t fix any errors present on the volume. To tell CHKDSK to fix the drive, we need to give it parameters. After your drive letter, type the following parameters separated by a space each: “/f /r /x”

CHKDSK Windows 8

The “/f” parameter tells CHKDSK to fix any errors it finds; “/r” tells it to locate the bad sectors on the drive and recover readable information; “/x” forces the drive to dismount before the process starts. Additional parameters are available for more specialized tasks, and are detailed at Microsoft’s TechNet site.

To summarize, the full command that should be typed into the Command Prompt is:

chkdsk [Drive:] [parameters]

In our example, it’s:

chkdsk L: /f /r /x

Note that CHKDSK needs to be able to lock the drive, meaning that it cannot be used to examine the system’s boot drive if the computer is in use. In our example, the target drive is an external disk so the CHKDSK process will begin as soon as we enter the command above. If the target drive is a boot disk, the system will ask you if you’d like to run the command before the next boot. Type “yes,” restart the computer, and the command will run before the operating system loads, allowing it to gain full access to the disk.

A CHKDSK command can take a long time, especially when performed on larger drives. Once it’s done, however, it will present a summary of results including total disk space, byte allocation, and, most importantly, any errors that were found and corrected.

CHKDSK Windows 8

The CHKDSK command is available in all versions of Windows, so those on Windows 7 or XP can also perform the steps above to initiate a scan of their hard drive. In the case of older versions of Windows, users can get to the Command Prompt by going to Start > Run and typing “cmd”.

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  • Handy Carry

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    • Madde

      trustworthy. lmao.

  • jamesdorr

    I just want to take this opportunity to personally thank Microsoft for hiding what CHKDSK is doing when you are repairing the primary partition. Not helpful. AT ALL.

  • Michael Lone-Wolf Werner

    I find chkdsk/r windows 8 seems to set at 27% for a long time now a hour, does not seem to work as well as other windows have in the past as I ran drive check and new drive sea gate tools or mini tool partition wizard drive fine only since Windows 8 seems to get issues other systems with 7 never like this. I get locked into this might try /f see if that is the same just had this on two different units using 8 HP laptop and home unit. I had even checked disc and wiped it clean totally windows 8 seems to act up wonder if that is why it put system into repair mode more often then should happen.

    • someone

      same problem with me, stops @ 27% for more than 4 hours, I had to shut it down !

  • Rodrigo Colpo

    I did what you said on my external HD, but now it has only 300GB, instead of 500GB. How can I have these 200GB back?

    • http://www.tekrevue.com/ TekRevue

      The CHKDSK command can segregate bad blocks on your hard drive. If after running this command you lost access to 200 GB, then that likely means your hard drive had a ton of bad sectors and may be on the verge of failing. You should back up your data and replace the drive ASAP.

      • Rodrigo Colpo

        I don’t think this is the correct reason why the size of my external HD has shrinked. Actually, every time I delete a file, the HD size shrinks again to the total size of all files together. I mean, there is never free space in my hard drive.
        Do you have another guess of what would be the solution for this?

        • Aaron Friedman

          TekRevue is correct Rodrigo. Sorry to inform you, but your disk is failing. Chkdsk isolates and prevents writing to bad blocks or sectors. It does that in an attempt to extend the life of the disk, giving you an opportunity to back up your data before it suffers catastrophic failure. With 200GB of failure, your drive is basically on life support. I would highly, highly recommend listening to TekRevue’s advice. Backup your data and replace the drive.

  • someone

    yeah same problem with me, stops @ 27% for more than 4 hours, I had to shut it down !

    • http://www.tekrevue.com/ TekRevue

      An inability to complete a CHKDSK command can indicate serious problems with the hard drive. It could also be the result of other system problems. Here are some things to try:

      1) First, back up your data. ANYONE who thinks they need to run CHKDSK should back up critical files ASAP.

      2) Try running the command from Safe Mode. Here are instructions for Windows Vista/7 http://windows.microsoft.com/en-us/windows/start-computer-safe-mode#start-computer-safe-mode=windows-vista and Windows 8 http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-including-safe-mode

      3) If you can, try removing the drive, mounting it in another computer (using a SATA to USB adapter or a direct internal SATA connection) and running the command from there.

      4) If all else fails and you can’t replace the drive, try third party disk utilities (I like GRC’s SpinRite https://www.grc.com/spinRite.htm but there are many others if you search around).

      • dt

        But what happens if i can execute the chkdsk command on boot (Recovery > Choose an option > Troubleshoot > Advanced Options > Command Line) which completes after 10-20 min but on normal boot i cannot skip scan & fix mode which stuck on 22%. Any ideas or the disk has actual a problem?

  • bharat

    thanks.. it worked. took 8 hours though, but now i can use the entire diskspace.

  • geomac

    You can speed up chkdsk by selecting chkdsk /spotfix C: since chksdsk is regularly running in the background and this spotfix parameter only checks segments with identified problems – AND it keeps you posted as to progress of the check/fix. This takes minutes rather than hours.

  • Mehdi

    It will NOT Allow you to fix errors on the C: drive bcs it is the OS drive and it says it is LOCKED!? This is only in the startup and command prompt (AFTER SPENDING HOURS JUST TO FIND OUT HOW, SINCE “PRESS F8 FOR SAFE MODE” IS HISTORY?)! Cannot boot to the full blown version of windows 8.1! Can MS fix that? I was only updating to 8.1 (from 8) when this new laptop crashed and has not booted since?
    Stupid windows 8 does not even have a restore point at all?? I want to go back to 7 but this stupid Asus laptop didn’t come with boot or OS system disk…these cheap goofy fly-by-night acting idiots! (Both MS and Asus and the rest of those who follow this rotted “system”)!
    This should not have and should never happen!
    All I did before the so-called upgrade I moved some large files around (from 2 to 30 MB A/V files from my iPhone) that’s all. I know this happened many times before to others since I was the technician at a large company before. SO Don’t move files under Windoze or else!

    • myname

      Sir you are just retarded, you can download every driver in the most unknown thing “Internet” and Windows 8 installs almost every driver alone.

  • aqil asraf

    i stuck at 12% for about 1 hour

  • Dana Jorgensen

    For those complaining about chkdsk getting stuck, previous versions did a 100% countdown for each of the five stages, while the Windows 8 version does a single 100% countdown for all five stages combined. Depending on how full the drive is, it will appear stuck at anywhere from 12% to 35% most of the time, starting in the 4th stage. Apparently Microsoft’s programmers decided to reserve most of the countdown for the last stage, which verifies free space. Use the “files processed” and “clusters processed” counters to observe progress instead in the last two stages.

  • Mur John-Paul

    I would like to point out that you don’t need /f because it is implied when you use /r

    from chkdsk /? : /R Locates bad sectors and recovers readable information (implies /F, when /scan not specified).

    • Ian Mortlock

      Two weeks ago I was sure I had an internal HDD problem. Reading/Writing of data to the drive became very slow. This was the sequence of my tracking down and fixing the problem.
      1, Ran WD “Data Lifeguard Diagnostics” as a full scan on my WD 500Gb HDD.(7 years old running Windows 8.1 This indicated sector errors on the drive.
      2. I immediately used Macrium “Reflect” to clone the drive to an external HDD
      3. Replaced the suspect HDD with a Seagate 2Tb internal unit
      4. Booted the PC from the External HDD and copied the clone to the new internal HDD.
      5. Used Windows 8.1 Admin tools to partition the extra 1.5Tb on my new Seagate internal HDD
      6. Rebooted my computer using the new Seagate HDD as boot drive.
      Problem solved. Great speed and performance restored.
      7. Formatted the suspect HDD. This showed 13 Gb not available after formatting.
      8. Ran chkdsk F: /f /r /x.
      This indicated 235 files in bad clusters.

      After 2 hours the process finished. The bad clusters were blocked from any further read/writes and I am up and running.

      Mur John-Paul. You said that /r implies /f. Back in the early 1980′s I learnt the /r located and tried to recover data only. If there is physical damage to the sector, /f will prevent data from being written to that sector where /r may not prevent data from being written there again. I might be an old man at 70 yrs. but I have been using Microsoft since Windows 1 in 1983.

  • chacha

    my external hard drive is not detected om my computer only on usb mass storage device. How do I check disk and fix on command prompt

    • http://www.tekrevue.com/ TekRevue

      Just to make sure I understand you correctly, when you plug in your external drive, your PC recognizes a “USB Mass Storage Device” but not the drive itself? If so, do you have data on the drive or is this a new drive?

      Try going to Disk Management to see if the drive shows up there. Go to File Explorer and right-click on “This PC.” Select “Manage” and then choose “Disk Management” under Storage. This will list all storage devices attached to the PC. Check to see if your external drive is listed here. If so, and if it doesn’t show up in Explorer, you may need to delete and reformat any partitions on the drive. Be careful, because this will delete any data.

      The problem may also be caused by a faulty controller on the external drive. If possible, try to open the external enclosure and remove the drive. Use another external enclosure or a USB to SATA adapter to try accessing the drive.

      If nothing above works, it may mean the drive itself has died. If you have important data on the drive and you don’t have backups, you may need to seek out professional data recovery services.

  • Aleisha Jane

    I ran the chkdsk through my External Hard-drive which had a Cyclic Redundancy Error and it’s finally finished, but I still can’t open my hard-drive. Not sure what to do now, as data recovery companies are so expensive, but there are important files I need to retrieve from this drive. Helppppp :c

  • http://www.chemicalpoisons.tumblr.com/ Αρχάγγελος Στεφανία

    Christ, I did all of the above, but some of the files I really wanted were deleted! I didn’t know I had to protect them, but even so, I still could not access my WD drive, cause it took ages to load.
    Tell me I can recover some of the files, otherwise I am going to kill something…

    • Jim Papageorgiou

      Oh darn, was it movies or work data? Let me guess WD external My Passport bought around 2010-2013 ? or regular HDD 3.5″ ?

      • http://www.chemicalpoisons.tumblr.com/ Αρχάγγελος Στεφανία

        I think a regular, it’s a pink one. I could check for you, just to be sure. I lost all my songs and some very valuable photos. :(