How to recover the partition table (Windows, Ubuntu) of an unallocated disc?

Question

The following screenshot shows the current state of my hard disc.

The unallocated part of the disc used to contain two operating systems:

• Windows and Ubuntu, in this order. Windows has been installed first. Ubuntu used Grub.
• I do not have information about specific partitioning.
• There was a home partition of Ubuntu was encrypted. I wrote down the passphrase.

The NTFS partition is not of interest for this question. I already managed to recover data stored there.

Do you know any tool for Linux or Windows which is capable of recovering the partitions? I assume that I lost the partition table or just Grub.

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Interim results

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Running testdisk

After running the Quick Search the following shows up:

Disk /dev/sdb - 500 GB / 465 GiB - CHS 969021 16 63

Warning: the current number of heads per cylinder is 16
but the correct value may be 255.
You can use the Geometry menu to change this value.
It's something to try if
- some partitions are not found by TestDisk
- or the partition table can not be written because partitions overlaps.

[Continue]

Then ...

Disk /dev/sdb - 500 GB / 465 GiB - CHS 969021 16 63
     Partition             Start        End    Size in sectors
 * HPFS - NTFS               2   0 33    205   3 19     204800
 P HPFS - NTFS             205   3 20 203174   9 41  204593152
 P Linux                203176  10 11 305359   3 51  103000064
 L Linux                313112   6  7 373707   2 50   61079552
   HPFS - NTFS          373707   2 51 969022  15 47  600078336
   HPFS - NTFS          373707   2 58 969020  15 63  600076329

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Success story

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Finally, I was able to recover the partition table. I cloned the drive using dd and had to change the geometry settings of the target drive. Then I was able to detect the Linux partitions on the cloned hard drive. Finally, I wrote the partition table via TestDisk to the clone hard drive. I did not want to alter the original drive to avoid total damage.

To actually mount and copy the data from the encrypted home partition I followed this post by rausch. Helpful background information can be read in: Unwrapping passphrase and inserting into the user session keyring failed.

Solution

Testdisk is your friend. A year ago, I fixed a broken MBR and faced exactly the same issue as yours (MBR's magic number got corrupted) with this tool. There are lots of live media containing it http://www.cgsecurity.org/wiki/TestDisk_Livecd.

Once you fix your issue, I suggest you backup your partition table with sfdisk. http://ubuntuwiki.net/index.php/Partition_tables,_managing_with_sfdisk

EDIT :Since I cant comment

Do a deeper search to see if everything is getting detected properly. It will take quite some time. If it doesn't, then you need to experiment with what the software suggests, at your own risk.

Be cautious when writing to partition table. If you have an external HDD, first boot with CloneZilla Live media on your computer, and make a bare-metal back up of your harddisk to the External disk before doing anything so that your internal hdd can be rolled back if you mess up.

Comments

[scjorge]

nice question-development-results-format!

[JJD]

Does testdisk take care of the encrypted home partition when I write the partition table to the disk?

[Jay Aurabind]

Looks like its possible, though not very straight forward. I never worked with LUKS encryption before. linuxquestions.org/questions/linux-general-1/…

[JJD]

I believe it makes sense to do a raw back-up of my disc with dd or some other tool before I write the partition table. I am afraid the encrypted home partition could get lost totally.

[Jay Aurabind]

Use clonezilla for bare metal backups