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i got problem about my PC, my pc use dual OS, but after I install windows the grub cannot detect my BAcktrack,my Backtrack location in /dev/sdaa4, I try to repair but error :

sudo su
mkdir /media/bt
mount /dev/sda4 /media/bt

error you must specify the filesystem type next i try another command

mount -t ext4 /dev/sda4 /media/bt

error again

wrong fs type, bad option, bad superblock on /dev/sda4, missing codepage or helper program or other error

So what can i do for repair my grub?

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migrated from Aug 9 '12 at 8:14

This question came from our site for professional and enthusiast programmers.

up vote 1 down vote accepted

The other answer is correct in the fact that Windows likes to think that it's the only OS on a PC.

What it really boils down to is popping your live CD back in, tell it to repair the Linux installation and that often does the trick.

In the future, I would always suggest the following order of events for setting up a multi-boot / OS PC:

  1. Linux LIVE CD Boot (pick a distro that you are comfortable with)
  2. Partition hard drive using the tools available on the live CD
  3. Install Windows on one of the designated partitions
  4. Install Linux (and / or other OS).
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Try to reinstall your Grub (Windows always delete the MBR):

sudo grub-install /dev/sda4

If this does not work you need your backtrack live CD.

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