HD has partition with RAW filesystem

[p-c]

I'm having a problem with a Samsung HD161HJ hard drive.

I'm running a Windows 8 installation that resides on an SSD located on the same computer in which the HD resides. The HD drive is labeled as D in Windows 8.
Everything has been working fine for the past couple of weeks, until something strange happened yesterday: the computer suddenly rebooted. Windows 8 gave a message something like this: "Your computer ran into a problem and needs to be restarted. We are gathering some information, and then we will restart for you".

Now, when I try to view the files in the HD drive (labeled as D in Windows Explorer) from the Windows 8 installation on the SSD, I receive the following error message:

D:/ is not accessible. The disk structure is corrupted and unreadable.

When I enter Event Viewer right after trying to access the HD files, there are several instances of the following event:

Event ID: 55; Source: Ntfs (Ntfs) ; Type: Error; Description: A corruption was discovered in the file system structure on volume D:. The Master File Table (MFT) contains a corrupted file record. The file reference number is 0x1000000000001. The name of the file is "<unable to determine file name>".

These errors are soon followed by instances of this event:

Event ID: 50; Source: Ntfs (Ntfs) ; Type: Warning; Description: {Delayed write failed} Windows was unable to save all the data for the file. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere

I ran the Command Prompt as an administrator, then tried to run

CHKDSK /R D:

but it gives me the following output:

The type of the file system is NTFS.
Unable to determine volume version and state. CHKDSK Aborted.

I tried to run Windows 8's Disk Management tool, and it shows the HD with 2 partitions:

- D: 149,04 GB RAW -- Healthy (Primary Partition)
- 9 MB -- Unallocated

I tried to run some file recovery tools. I ran MiniTool Power Data Recovery 6.8, and it found all the files of my HD. I was able to recover everything I needed (a few files that I had neglected to backup in time). I also tried to run MiniTool Partition Wizard, and it showed all my files as if there wasn't any problem. So, the files seem to be all there without any damage -- I don't know why CHKDSK seems incapable of recovering it, while MiniTool accesses the whole file tree with no trouble.

How can I find out what exactly went wrong with this HD and how to fix it?

 

[Lumia925]

Install HD Sentinel from here http://www.hdsentinel.com/ (you can install the trial version if you dont want to spend $$)
Launch HD Sentinel as Administrator, and check the smart page.
Post your findings.
If you have managed to recover all the files, try formatting the drive.

 

[p-c]

I ran HD Sentinel Trial version.
For the HD, the Overview tab says: "There is 1 weak sector found on the disk surface. It may be remapped any time in the later use of the disk. 134 errors occured during data transfer."
The SMART page for the HD is in this PicPaste link.

 

[Lumia925]

According to the smart report, there is a pending sector on the drive. There are 134 reported uncorrectable errors (HEX 86 is equivalent to decimal 134). The drive has problems, and that's what probably caused the partition to get corrupted. Format it. Don't use the quick format, do a full format, a full format should remap the pending sector to a spare sector. If the remap is successful, the pending sector count will return to 0, and both reallocated sectors count and reallocation event count should go up to 1.
Once the format completes, the drive should be usable, assuming there aren't hidden errors. If the drive is usable after the format, open HD Sentinel, select the drive in question, on top click "Disk" -->> "Extended self test".

 

[p-c]

Lumia925, thank you for the reply.
After recovering all the necessary files, I ran the full format on the HD. Now, HD Sentinel shows that the Pending Sector Count dropped to 0, but both the Reallocated Sectors Count and the Reallocation Event Count remain at 0 (instead of rising to 1).
The CHKDSK file system check, however, didn't report any errors in the file system of the newly formatted HD.