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My external HDD suddenly started reporting as "931.51 GB RAW (Primary)" in Windows disk management.

I tried using DiskInternals Partition Recovery, which indeed reported the drive being only seen as RAW, easily found a partition at sector 2048, spanning the full size of the disk, detected an NTFS system on it... and then it completely failed to find any files.

DISKPART sees the partition as RAW.

ChkDsk H:, however, DOES detect it as NTFS and checks the filesystem (finding indexing errors in file descriptor 5, which is root folder ".", so thus far I only ran it in read-only mode out of caution).

MiniTool, another recovery program, immediately noticed the disk, with a correct volume label and explorable contents, even without running a recovery pass, but the free version doesn't let me copy files.

Finally, TestDisk is able to read the disk's contents without any problems, without running a specialized recovery pass - it accesses the NTFS system as if everything was fine.

Reading the disk in hex mode, I see the MBR area is completely empty (all zeroes) except for a serial number and one, seemingly correct, partition entry:

0000000000: 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00
....
00000001A0: 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00
00000001B0: 00 00 00 00 00 00 00 00 │ 39 72 8E 13 00 00 00 20  <- serial, part.type
00000001C0: 21 00 07 FE FF FF 00 08 │ 00 00 AC 65 70 74 00 00  <- partition 1
00000001D0: 00 00 00 00 00 00 00 00 │ 00 00 00 00 00 00 00 00
00000001E0: 00 00 00 00 00 00 00 00 │ 00 00 00 00 00 00 00 00
00000001F0: 00 00 00 00 00 00 00 00 │ 00 00 00 00 00 00 55 AA  <- magic
....
00000FFFF0: 00 00 00 00 00 00 00 00 │ 00 00 00 00 00 00 00 00
0000100000: EB 52 90 4E 54 46 53 20 │ 20 20 20 00 02 08 00 00  <- NTFS

The partition is of type 07, so it's NTFS, starts at sector 2048, and actually the filesystem is still there - at offset 0x100000 (2048*512 sector size) a nice NTFS system starts. So it seems all to be there.

From the looks of it, I'd expect Windows to see the disk as an NTFS partition and maybe require a filesystem check - not see it as not formatted at all.

Does that mean that the disk is readable and fine, but somehow Windows can't access it? Or did Windows cache the MBR (as I have not rebooted the machine yet)? Or maybe I don't even need an MBR, since this is not a bootable drive, merely an external USB storage unit?

What should I do to make Windows recognize the NTFS partition, if it's all there, intact and apparently healthy enough to be read without sector-by-sector recovery passes? Should I let chkdsk H: /f run and maybe try to fix it? (I haven't tried yet, as I heard chkdsk destroys data in some fringe cases)

(This is not a generic "how do I recover my data?" question, recovery wasn't that big of an issue in this case, as there was no unique data on that disk - it's more of a "what's missing, why doesn't it work, can it be fixed instead of recovered?" question. Most "RAW partition" trouble reports involve CHKDSK refusing to operate on a RAW partition; here, CHKDSK works fine, oddly enough.)

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  • TestDisk, in Filesystem Tools mode, is able to extract files just fine, and I'm backing stuff up right now, thanks a lot! However, I'd still like to try to "fix" it, if possible, even if just to see if it can be done. It makes me awfully curious how Chkdsk or TestDisk is able to read the filesystem without any issues or "advanced recovery", while Windows itself sees the partition as RAW.
    – Sinus the Tentacular
    Commented Mar 31, 2018 at 14:05
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    OK short version since the Q is closed now, Chkdsk does not look at the partition table but it looks at the MFT entries directly. So does Testdisk which mainly searches for partition boot sectors (the first and the last in case of a NTFS file system). For a more detailed discussion, see Section 1.3 of my MSc thesis.
    – Andrea Lazzarotto
    Commented Apr 1, 2018 at 15:53

3 Answers 3

Reset to default
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In the end, after I used TestDisk to copy all the important files off the disk, I finally risked running chkdsk /f and it didn't detect any problems, but apparently removed the "requires checking" flag set after a careless disconnection, and so afterwards the disk was perfectly fine.

I felt a bit silly afterwards, having gone all PhD on the disk, when all it needed was a routine check, but maybe the disk-salvage tools should be able to recognize the "requires checking" flag...

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  • Same issue after bad USB enclosure kept dying and corrupted the partition. Fixed with eSATA enclosure and that command.
    – Ray Foss
    Commented Jan 10, 2020 at 21:41
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    WARNING: running this command can be really dangerous and I just got the consequences of it. I ran this command and chkdsk restored my partition but found many errors which it recovered by writing the recovered files in a found.000 folder. These recovered files have OVERWRITEN some other files that could have been recovered by a dedicated tool. Now, if I run such a tool, it says the files are unrecoverable because they have been overwritten by the ones in found.000. If I had known that, I wouldn't have run chkdsk.
    – Nicolas Cadilhac
    Commented Dec 5, 2020 at 2:00
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From How to Fix RAW SD Card or External Drive: Ultimate Solution [MiniTool Tips]:

When Windows is unable to read or mistakenly read any of these 3 places, Partition Table, Partition Boot Sector, and File System, it will report the corresponding partition as RAW

If it is due to partition table issue, you need to repair partition table.
If it is due to file system error, you need to fix file system.
If it is caused by boot sector issue, you need to fix boot sector.

I got most information from the above post. Maybe it explains what you want to know.

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  • 7
    -1. Link-only answers are low quality. Please edit your answer and make it self-contained, cite the crucial parts of the linked article here. And make sure it does answer the question (as opposed to maybe).
    – Kamil Maciorowski
    Commented Apr 24, 2018 at 6:41
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    This is spam. I see this linked everywhere.
    – m4heshd
    Commented Jan 4, 2021 at 22:03
  • Many (but not all) of the suggestions involve using their Mintool Partition Wizard. There is a free edition, although at least some of the suggestions require the paid-for version (which I can't personally vouch for). It's difficult to skim-read the blog, but there may be some useful info there.
    – mwfearnley
    Commented Mar 3, 2023 at 14:00
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In your case, I would recommend to you use initialization of the disk. Open Disk management as you deed already. click on the disk and select initialize diskhow to initialize disk in w10 Not sure about other recommended software, but this Diskinternals partition recovery tool https://www.diskinternals.com/partition-recovery/solution-for-raw-partition-recovery/ is what you will need to rebuild file system and data restore (I have no idea if I am allowed to put a link here, I usually read - not answer). Good luck!

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    Is this a case of “We had to destroy the village in order to save it” or “The medical treatment was a success, and we cured the disease; however, the patient died”?    Disk initialization sounds like a nuclear option, not a search and rescue operation.
    – Scott - Слава Україні
    Commented Mar 28, 2019 at 13:50

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