unreadable hard drive partition. is partition table corrupted?

I have a hard drive that had 2 partitions C drive and D drive. My internet stopped responding, so I restarted my computer. However, my computer acted like it no longer recognized my C drive and that there was no operating system. I had a Windows 7 disc in the dvd drive and it automatically loaded. I tried clicking through to see what happens and it wouldn't even allow me to install on the C drive saying it was not bootable or something.

I installed another hard drive and installed Windows 7 on that. I connected my old hard drive using a usb adapter and both old C and D drives connected. D drive was accessible and I could read the files on there no problem. C drive had a popup telling me to error scan the drive. I did but nothing happened. Also, even though C drive connected (and is technically H drive now) and was visible in My Computer, I cannot see its contents. Drive properties says 0 bytes used, 0 bytes free.

Are my files still recoverable on the old C drive? Is it just the partition table being corrupted?

gavsiu

Posted 2012-01-04T23:30:27.440

Reputation: 147

Answers

A couple ideas:

Check the partition table with Testdisk : http://www.cgsecurity.org/wiki/TestDisk
Try having a look from a Linux based rescue CD. e.g., http://www.sysresccd.org It should give you more information about what's actually left on the disk.

If there's anything important on the drive, you should try taking a snapshot with a utility like 'dd' before attempting data recovery. (if you've never used it, you can use it from a Linux system to copy the raw image of your drive to a file... provided you have the available storage. This will take a very long time to complete)

Good luck and be careful.

This is a sample of the output of testdisk against my own system:

TestDisk 6.13, Data Recovery Utility, November 2011
Christophe GRENIER 
http://www.cgsecurity.org

Disk /dev/sda - 640 GB / 596 GiB - CHS 77826 255 63
     Partition               Start        End    Size in sectors
>D HPFS - NTFS              0  32 33    41 254 63     672682 [SYSTEM_DRV]
 D HPFS - NTFS             41 207 39 74533 254 63 1196716966 [Windows7_OS]
 D HPFS - NTFS          74533  77 41 75492 254 63   15417509 [Lenovo_Recovery]

mgjk

Posted 2012-01-04T23:30:27.440

Reputation: 1 337

Will accessing the D partition ruin my chances of recovering my files from C partition? – gavsiu – 2012-01-05T00:53:08.680

Accessing it, no. But be paranoid... I would not attempt to repair your C: partition until your D: partition is backed up. The two partitions are recorded on the same partition table. What does testdisk say? I ran a test against my own system. I added the output of a scan of my own partitions to my comment. Could you post what it says about your messed up drive? – mgjk – 2012-01-05T14:29:15.887

@gavsiu: most likely not, but in extremely severe cases (where the head stack of the drive is about to fall apart) - yes. However, if you can browse D, then it's not that bad. Due to that, making an image with dd here might be a bit excessive and probably not needed in your case. – XXL – 2012-01-05T14:36:06.507

@XXL agreed, it depends on the importance of the data though. If the C: drive has the only copy of the family photos... then take a dd. Technically, reading should be safe. Any attempts to perform recovery might trash the C: and D: partition, particularly if you're unsure of the tools. – mgjk – 2012-01-05T14:53:51.403

I mistakenly clicked the scan and repair button that pops up in Windows 7 when a drive that has not been cleanly unmounted is detected for the C drive. The files on there are not as important since I only store Windows and program installations there. I just wanted to back up some settings. After the scan and repair finished, the only folders that came back partially was the x64 version of Program Files. Whatever, I've already written it off. My files and photos are still accessible on the D drive. – gavsiu – 2012-01-08T21:07:08.957

Try running GetDataBack and see if the scan shows your partition & data. The software is commercial but you'll be able to see your files and open individual files 1 at a time without paying anything.

Also, TestDisk is a more technical but free software that might be useful to investigate, since it can recover lost partitions and more.

Syclone0044

Posted 2012-01-04T23:30:27.440

Reputation: 1 222

check to make sure the old drive still has the boot flag set and you might even want to try to rebuild the MBR.

nhutto

Posted 2012-01-04T23:30:27.440

Reputation: 293

For future reference, to remove the confusion between actual physical drives - the so-called C and D drives are actually volumes.

Now, by the looks of it, the hard drive in question has developed bad sectors. That can explain the various anomalies you are currently witnessing. It very well might have triggered MBR corruption, as suggested by user nhutto: however, less likely a partition table corruption (seeing as your volumes are still identified), but more likely trouble with the boot prerequisites (Windows` boot manager/loader decay, for W7 this is a separate partition called "System Reserved" of about 100M, can you see it?) - only considering these things separate in the context. Either way, all of this (most likely) leads to the damaged filesystem.

If you want a quick plan of action, then follow the instructions posted by Syclone0044. If the MFT of NTFS isn't badly damaged - GDB should be able to expose the persisting contents.

A sort-of bruteforce Windows-only way would be to run chkdsk /F /R over the troubled volumes. After that, you can try rebuilding the MBR, along with the boot loader. Finally, you can try accessing the filesystem or even booting normally (sfc /scannow might come of help as a last resort).

The long route to take is to first identify the disks SMART attributes - that can either be done with HDDScan (as it can work with USB drives) or from a live Linux distro with the smartmontools package. This will give you an assessment of overall health of the drive and give you clues as to what might have happened (a point of interest is probably -> Current Pending Sector Count, Reallocated Sectors Count, Reallocation Event Count). Using the distro is beneficial, because you'd also have the hands-on ability to try mounting the NTFS filesystem with ntfs-3g pkg. If that fails - inspect the error message and run chkdsk with the aforementioned params. After that, it will probably become mountable, unless the drive/filesystem is in a really bad state.

XXL

Posted 2012-01-04T23:30:27.440

Reputation: 1 359