Ubuntu – Why does installing Grub2 give an “ISO9660: filesystem destruction…” warning

12.04grub2

I have installed Ubuntu 12.04 on my computer, but at the end of the installation it gave me an error and it didn't install grub2.
Now I'm trying to install it using the live cd:

This is my sudo fdisk -l:

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x6af447e6

Device Boot Start End Blocks Id System

/dev/sda1 * 2048 781459455 390728704 7 HPFS/NTFS/exFAT

/dev/sda2 781459456 789272575 3906560 82 Linux swap / Solaris

/dev/sda3 789272576 976773119 93750272 83 Linux

After mounting and chroot the linux partiton, I give grub-install /dev/sda command, and I get:

/usr/sbin/grub-setup: error: hd0 appears to contain a iso9660 filesystem which isn't known to reserve space for DOS-style boot. Installing GRUB there could result in FILESYSTEM DESTRUCTION if valuable data is overwritten by grub-setup (–skip-fs-probe disables this check, use at your own risk).

(same error even with grub-install –recheck /dev/sda)

What can I do?
I also tried boot-repair, but I get this error:
http://paste.ubuntu.com/1069353/

Best Answer

It appears that you somehow got an iso9660 filesystem header written into your hard disk's boot track. Since your first partition starts at sector 2048, and you are using the conventional msdos partition table, you can eliminate it by writing zeros to sectors 1-2047 with the following command:

sudo dd if=/dev/zero of=/dev/sda bs=512 seek=1 count=2047