What is this Raw File System

What is this Raw File System

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Sometimes a damaged volume may look like it lost its file system and CHKDSK tool will complain that file system is raw

The type of the file system is RAW.

this is a curious issue as seen here


what the hell is a RAW file system?—


what the hell is a RAW file system?—is easy enough to answer. It's simply a disk partition that has not been

formatted with an NT file system, neither FAT nor NTFS.


so what is this raw or as said raw file system, it is nothing but a system supplied file system driver that is the

"last resort" for all I/O requests requiring file system support. When the I/O manager calls active file systems

 to mount a volume, RAW is always called last because it supports all disk and tape media.

However, RAW supplies very primitive file handling capabilities. That is, it does not impose any on-disk file

structure or metadata structures for the information about the media; it simply allows read/write access

to the logical blocks on the physical disk. For example, it treats the whole disk as a single file and supplies

physical-disk-level access to the disk.


If a device is being driven in raw mode, it has no function driver and no upper or lower-level filter drivers.

All raw-mode I/O is done by the bus driver and optional bus filter drivers.


Note, however, that a bus driver does not handle read and write requests for the devices on its bus.

Read and write requests to a device are handled by the device's function driver only. Only if the device

is being used in raw mode does the parent bus driver handle reads and writes for the device.

ok the above extract is from DDK ...now lets see where can i see this happening





here you see that it is for rawtape, rawcdrom, rawdisk (I am using device and driver explorer here )





so how can i reproduce this issue--raw file system reported by chkdsk --we can use dskprobe from http://technet2.microsoft.com/WindowsServer/en/library/006902f1-bae9-4055-9ad2-123ea19006b71033.mspx 

and repro this issue ( please do not try this on a production or home machine -you may loose data)

There are two places where we store file system information as seen below

1 MBR partition Table

2 Volumes' boot sector

When the file system information provided on these 2 sectors of disk is not good you may see chkdsk reporting raw file

system (though the data is still there)








A Raw volume is a volume that was never formatted and does not contain a File System



so just to play i did same on my test machine and removed OEM ID string on D drives Volume boot sector and yes this is

my production machine containing lots of data, Now when i try to access D drive it asks do you want to format it...

..Of course NOT

As if we format we will lose all the data on D drive.

I tried running Chkdsk and you can see results below. It says, type of File System is raw. Chkdsk is not available for raw drives.

I reversed my changes using dskprobe again (added NTFS IN OEM ID string) and Yes my data is back and D drive is  accessible.




Gaurav Anand

This posting is provided "AS IS" with no warranties, and confers no rights.

  • hi:

    I have problems like you had with the drive file system not recognized. I tried to

    run dskprobe but I can't find it on my system. I have a win 2000 pro with sp4 and

    dskprobe is not there. Is it possible that you send me a copy of it with any other

    file required to run it. I have a lot of data on my disk and I don't want to loose it.

    Another thing, this 'device and drivers explorer' what is it and how can I get a

    copy of it?

    Please, mail me some info. my e-mail is     sgt_fig1@hotmail.com     I promise that

    NOTHING illegal will take place.

    Thank you for any help that you may give me.


  • I have a problem with my disk. Same problem as yours, but i can't find the diskprobe, can you gave an idea, where i can find those files. and also the device and drivers explorer. what is it? how can i get thoses file? can you send me those files. thanks! catherinerodil@yahoo.com

  • Hi I have a problem of flash disk that says its RAW file system and i cannot format it plz help me.

  • Looks like that the dskprobe is only available in Windows XP and Windows Server 2003. I hope it works on xp because i can try it on another computer. If only on 2003 im el'screwdo.

  • i downloaded dskprobe from here


  • And the DeviceTree

    i downloaded from here


    you have to register

  • I had trouble finding Diskprobe (even online from Microsoft).  After some research and some thinking, I decided to search my computer for a copy.  I found it on the new CD that I made when I slipsreamed Windows Service Pack 3 onto my original Windows XP CD.  You can check your cd for a copy.  It may be on older versions as well.  Look under Support Tools.

  • i use a netac 2gb pendrive and it just stoped workin. i tried formatin it and it said can not cos it was  a raw system

  • I have the same problem and i have a pc with SP2. i cant find any of those programs. i have that RAW problem with a 500GB Segate and i have over 100GB of important files please can you explain how to get them back without deleting the file on there because the above is kind of hard to understand. thx

  • i just wanna take my files back, when ever i try to explore my partition, it says do u want to format it  now, and yes its RAW file system,

    i just wanna take backup for my files and i don't care about the hard disk.. please help. e-mail me there Careless00045@yahoo.com thanx alot.  

  • Yeah I'm trying install a webcam of mine and the installation CD says File System: RAW meaning it can't be read.

    It said Windows cannot read the disk.

    Can somebody help me?

  • i have to donelod to rowfilesystem

  • Hey, my 500gb seagate hard drive is a RAW file as well. I try and reformat the drive, but it won't allow me to do so. I can view the files as a read only file on Macs but not on PC. On PC it won't allow me to do anything to the drive, not even change some permissions. If anyone has a solution e-mail me at iamfoxy2004@hotmail.com Thanks.


  • ok well.. these tools would be nice if i knew exactly where to find the right sectors and what not..

    my laptop hdd is the one with the problem.. it boots into windows just fine.. but when i try to schedule the chkdsk through the drive properties it just closes on me and doesnt ask to schedule.. so i type it in the cmd prompt. it asked me there so i say yes of course..

    when i restart it to do the chkdsk it says its RAW and whatnot..

    ive been looking all over for the solution.. i even tried running ZAR and still no luck.

    plz help.. ?  my email is austalapasta@gmail.com

  • what can be done to solve the problem of RAW filling system

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