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I got my Ubuntu 12.04 corrupted after a sudden power cut. I've tried to retrieve my data from a live USB but I am not able to mount my main disk (/dev/sda1). It gives me a error about a bad super block and something like that.

Please provide me some assistence on this as I am not sure how to proceed. I just want to retrieve my data.

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Please post the exact error, and if possible a screenshot. – saji89 Jan 2 '13 at 10:23

Linux partitions have a backup of the superblock.

Try typing sudo dumpe2fs /dev/sda1 | grep superblock

You should get something like this:

 Primary superblock at 0, Group descriptors at 1-6
  Backup superblock at 32768, Group descriptors at 32769-32774
  Backup superblock at 98304, Group descriptors at 98305-98310
  Backup superblock at 163840, Group descriptors at 163841-163846
  Backup superblock at 229376, Group descriptors at 229377-229382
  Backup superblock at 294912, Group descriptors at 294913-294918

Try repairing the partition using the backup superblock:

sudo fsck -b 32768 /dev/sda2

Only run this and other fsck commands while your file system is unmounted. Make the necessary changes to the block number according to your dumpe2fs output.

When it's ready, try mounting again. Hope this helps.

Source: Linux: Recover Corrupted Partition From A Bad Superblock

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You can also force the system to perform a full filesystem check on the next reboot by doing this:

$ sudo touch /forcefsck
$ sudo reboot
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I don't see how he can create a new file on a filesystem he isn't able to mount in the first place. – gertvdijk Jan 2 '13 at 20:18

You should be at a command prompt when you get the error, if not try and get into one ('press M for manual recovery' maybe). Type 'fsck' and press enter. If that doesn't work, type 'sudo fsck' and press enter. If it asks for your password, enter it (it will not be visible) and press enter. Good luck!

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