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What Does “CHKDSK Is Not Available for RAW Drives” Mean?

Why CHKDSK can’t do what you’re asking.

CHKDSK on a RAW drive.
CHKDSK on a RAW drive. (Screenshot:
CHKDSK can't check an empty drive, and Windows considers RAW to mean empty.
Question: I’m having a problem with my external drive, so I ran “CHKDSK K: /F” on it. It gave me an error: CHKDSK is not available for RAW drives. What? Why? What am I supposed to do?

Windows thinks your drive isn’t formatted and has no data on it. Even the system overhead information telling Windows the location of your data is missing.

That can happen for a variety of reasons.

If you expect there to be data on that drive . . . the news may not be good.

It’s time to break out another tortured metaphor.

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Dealing with RAW drives

A drive appearing as RAW means Windows thinks the drive is unformatted and has no data. If that’s accurate, format the drive. If that’s not accurate, try different connections or machines to try to get it to work. In the worst case — hardware failure — you could be looking at a data recovery service or data loss.

RAW drives

Windows needs disks — internal or external — to have overhead information on them that tells it where your data is stored. The process of setting up that data is called formatting.

Think of it a taking an expanse of bare land and putting streets on it. Nothing more, just streets. You may have seen new housing developments at this stage of construction: no buildings anywhere, but acres and acres of streets.

The streets are the land’s “format”.1 They tell the housing development where it can build houses on the land.

A RAW drive has no format. There are no “streets” for Windows to use to place or locate files.

A RAW drive is the disk equivalent of bare land.

A RAW or unformatted drive in Disk Manager.
A RAW or unformatted drive in Disk Manager. Click for larger image. (Screenshot:


CHKDSK works on streets. To stretch the metaphor, it walks the “streets” on the disk, making sure they’re all properly maintained, that all the houses can be found, that stop signs are where they should be, and that there are no oddities like one-way dead-end streets.

With the “/F” switch, it’ll try to fix the problems it finds — perhaps moving streets around, perhaps connecting up abandoned streets, and otherwise doing the best it can to make sure the disk system of streets is all in good working order.2

But CHKDSK needs the streets to have been started in order for it to do its work. Its job is to check or fix a file system, which means there needs to be a file system to be checked or fixed.

A RAW drive has no file system, and is the equivalent of bare land with no streets at all.

Dealing with a RAW drive

How you deal with a RAW drive depends on your expectations and whether you think the drive has data on it.

If you know the drive is empty, the solution is simple: format it. There are several ways; the most common might be to right-click on the drive in Windows File Explorer and click on Format. Once done, you can run CHKDSK if you like, though there should be nothing for CHKDSK to fix. The streets have been newly paved.

If you believe the drive should have data on it, things get more difficult. My External HDD Shows Not Formatted — But It Has All My Data! goes into more detail, but in summary, you’ll want to:

  • Try connecting the drive using a different USB slot.
  • Try connecting the drive using a different USB cable.
  • Try connecting the drive to a different computer.
  • Try moving the drive to a different external enclosure.
  • Try data recovery tools on the drive.
  • Try a data recovery service, if the information is valuable enough.

Depending on if and how you’re able to get it to work, you can isolate the problem and also decide if it’s time to replace the drive.

I’d be remiss if I didn’t say that getting to that last item in the list means you weren’t backing up. Backing up before problems arise makes any data loss a complete non-issue.

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Footnotes & References

1: As all metaphors must be, this is a gross oversimplification. It doesn’t account for different types of formatting, like FAT32, exFAT, or NTFS. Also, a newly formatted disk is really more like the land having an entrance and nothing else — streets are really built (and removed!) as houses are constructed and destroyed. Fortunately, that’s not really important here.

2: As long as we’re torturing our metaphor, you might consider “/R” the equivalent of looking at every square inch of both the streets and the rest of the land, looking for potholes and land mines, fixing what it can, and setting up “Do Not Go Here” signs for everything it can’t.

6 comments on “What Does “CHKDSK Is Not Available for RAW Drives” Mean?”

  1. One thing to try to recover the data is Recuva. If there’s data on the disk, the streets might be there even if the street directory (exFAT, NTFS, or FAT32) says they’re not. If the data is there, Recuva might be able to recover some or up to all of it. Although all of it might be overly optimistic.

  2. I’ve had a case where a drive appeared as RAW or unformatted because the MBR got corrupted. With luck, I was able to restore it and get the content back… I then got a new drive and moved it’s entire content to a new drive. That old drive finally died the next week.
    THEN, I started using a backup utility, set to run every night, and a backup drive.
    That was my wake up call that convinced me to do proper backups.

  3. Hey My external device is not working properly .. the problem is the device is RAW file system and it is displaying a wrong size ..unable to format …if you are will I need your help.


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