[SOLVED] Partition table deleted or corrupted.

[leorolla]

I have also posted at Ubuntu Forums
Thanks in advance for any help!

Hello everyone,

Yesterday I was trying to get SGD running from a pendrive without success. Nothing was wrong with my PC, but I wanted an SGD just in case.

I ended up trying the "Smart BootManager" version 3.7 listed by unetbootin.

From SmartBootManager I selected a given partition and chose "boot it", it asked whether I wanted to save it (sic), I said yes and after that I can't
read my HD.

When booting, I have a grub-rescue> prompt, it knows I have (hd0) but it freezes when I try to look into it. That's all my PC is doing at the moment.

I have booted from a standard Ubuntu Karmic installation USB. I have run:
sudo fdisk -l
sudo apt-get install testdisk
sudo testdisk
sudo apt-get install gpart
sudo gpart /dev/sda

Now fsdisk is reporting "This doesn't look like a partition table Probably you selected the wrong device."

And the starting/ending cylinders reported by fsdisk are different from those reported by testdisk and gpart.

I remember that in the past I had problems after using gparted (not gpart), after resizing a given partition. It was solved by some brute-force
method (like resizing the neighboring partition as well or something like that).

Is this natural to have a +1 cylinder difference between fsdisk and testdisk/gpart ?

What is the most safe way to recover it in this case ?

Thanks!

PS: Logs can be found at Ubuntuforums thread 1427150

Briefly,

$ sudo fdisk -l

Disk /dev/sda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xd3ffd3ff

This doesn't look like a partition table
Probably you selected the wrong device.

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   ?           1        3262    26201983+   7  HPFS/NTFS
/dev/sda2            3263       10717    59882287+   b  W95 FAT32
/dev/sda3           10718       14423    29768445   83  Linux
/dev/sda4           14424       14593     1365525   82  Linux swap / Solaris

Disk /dev/sdb: 8006 MB, 8006926336 bytes
255 heads, 63 sectors/track, 973 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000d3b5b

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         819     6578586    b  W95 FAT32
/dev/sdb2   *         820         952     1068322+  1b  Hidden W95 FAT32
/dev/sdb3             953         970      144585   1b  Hidden W95 FAT32
/dev/sdb4             971         973       24097+  16  Hidden FAT16
$ sudo gpart /dev/sda 

Begin scan...
Possible partition(Windows NT/W2K FS), size(25587mb), offset(0mb)
Possible partition(DOS FAT), size(58478mb), offset(25587mb)
Possible partition(Linux ext2), size(29070mb), offset(84066mb)
Possible partition(Linux swap), size(1333mb), offset(113137mb)
End scan.

Checking partitions...
Partition(OS/2 HPFS, NTFS, QNX or Advanced UNIX): primary 
Partition(DOS or Windows 95 with 32 bit FAT, LBA): primary 
Partition(Linux ext2 filesystem): primary 
Partition(Linux swap or Solaris/x86): primary 
Ok.

Guessed primary partition table:
Primary partition(1)
   type: 007(0x07)(OS/2 HPFS, NTFS, QNX or Advanced UNIX)
   size: 25587mb #s(52403952) s(63-52404014)
   chs:  (0/1/1)-(1023/254/63)d (0/1/1)-(3261/254/48)r

Primary partition(2)
   type: 012(0x0C)(DOS or Windows 95 with 32 bit FAT, LBA)
   size: 58478mb #s(119764575) s(52404030-172168604)
   chs:  (1023/254/63)-(1023/254/63)d (3262/0/1)-(10716/254/63)r

Primary partition(3)
   type: 131(0x83)(Linux ext2 filesystem)
   size: 29070mb #s(59536888) s(172168605-231705492)
   chs:  (1023/254/63)-(1023/254/63)d (10717/0/1)-(14422/254/61)r

Primary partition(4)
   type: 130(0x82)(Linux swap or Solaris/x86)
   size: 1333mb #s(2731048) s(231705495-234436542)
   chs:  (1023/254/63)-(1023/254/63)d (14423/0/1)-(14592/254/61)r

$ sudo testdisk

[... print scren:]

TestDisk 6.11, Data Recovery Utility, April 2009
...
...

Disk /dev/sda - 120 GB / 111 GiB - CHS 14593 255 63
Current partition structure:
     Partition                  Start        End    Size in sectors

 1 * HPFS - NTFS              0   1  1  3261 254 63   52403967 [WINDOWS]
 2 P FAT32                 3262   0  1 10716 254 63  119764575 [DATA]
 3 P Linux                10717   0  1 14422 254 63   59536890
 4 P Linux Swap           14423   0  1 14592 254 63    2731050









*=Primary bootable  P=Primary  L=Logical  E=Extended  D=Deleted
[Quick Search]  [ Backup ]
                            Try to locate partition

[devils casper]

/dev/sda1 ? 1 3262 26201983+ 7 HPFS/NTFS

Boot up from PartedMagic LiveCD/USB and set boot flag for /dev/sda1 partition. Right click on /dev/sda1 and select set Boot flag.

Have you tried to mount any partition?

[leorolla]

Boot up from PartedMagic LiveCD/USB and set boot flag for /dev/sda1 partition. Right click on /dev/sda1 and select set Boot flag.

Have you tried to mount any partition?

Thanks for the reply!

I can't access the partitions to start with. I had my partiton table ruined by this "Smart BootManager 3.7". So to answer the question, I did not really try to mount it, but Ubuntu Live installation CD probably tried while loading.

ubuntu@ubuntu:~$ ls /dev/sd*
/dev/sda  /dev/sdb  /dev/sdb1  /dev/sdb2  /dev/sdb3  /dev/sdb4
ubuntu@ubuntu:~$

Note: sdb is the pendrive I have booted from (yes, it has partitions)

GParted sees a plain device, as well as Palimpsest Disk Utility.

testdisk could recognize the partitions. It could even read the files inside.

I am not sure if the first partition was flagged bootable before (in spite of its name, there is nothing there, only Ubuntu on the 3rd partition), or if it was SmartBootManager that tried to set this flag.

[leorolla]

Fixed!
Thank you for the help.
I'm posting from the recovered install.

First I did a backup of the partition table, then I ran testdisk, followed the standad procedure, and told it to write to the partition table.

Everything working fine as before

[devils casper]

Well Done !

testdisk is a very good partition recovery tool. It worked fine for me everytime.