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Possible Duplicate:
Grub rescue - error: unknown filesystem

I have had bad experiences with 12.04 on my laptop, too many things just dont work so am wiping it and replacing with Windows 8 release preview to get it running again. Anyway, I installed normally, deleted partitions and formatted and installed windows fine, but now there is an error coming up when it boots:

error: unknown filesystem
grub rescue>

Ive tried repairing from Windows 8 disk, doing FixMbr and FixBoot but hasnt worked, neither has reinstalling.

Any ideas how to get rid of this?

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marked as duplicate by jokerdino, stephenmyall, Ringtail, Tom Brossman, belacqua Nov 2 '12 at 16:26

This question was marked as an exact duplicate of an existing question.

Boot from a Ubuntu LiveCD and open a terminal, type sudo fdisk -l and post the results on your question. – Bruno Pereira Jun 1 '12 at 9:51
The standard behavior of Windows is to write its own boot loader to the MBR on installation. Unless Windows 8 has added an option not to do this, you may have found a bug in the Windows 8 Release Preview. You could see what help is available through Microsoft support, and in forums for users of Windows 8. Otherwise, creating a new partition table on your drive (with GParted on the Ubuntu live CD) will wipe everything out, but should fix the problem. I'm posting this as a comment rather than an answer with the hope that someone will be able to furnish more helpful advice. – Eliah Kagan Jun 1 '12 at 9:52
Results of sudo fdisk -l: – Shane O'Connor Jun 1 '12 at 10:20
Disk /dev/sda: 500.1 GB, 500107862016 bytes Disk identifier: 0x000726f0 Device Boot Start End Blocks Id System /dev/sda1 2048 976771071 488384512 7 HPFS/NTFS/exFAT Disk /dev/sdb: 8036 MB, 8036285952 bytes 255 heads, 63 sectors/track, 977 cylinders, total 15695871 sectors Units = sectors of 1 * 512 = 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 * 44 15679439 7839698 b W95 FAT32 – Shane O'Connor Jun 1 '12 at 10:35
Sorry, how to I enter this and retain format? backticks doesnt seem to work? – Shane O'Connor Jun 1 '12 at 10:36

You’ll need to get your Windows 7 or Windows Vista retail disc or download the free recovery media from

Note: If you don’t have a retail disc with your computer, and instead you had to make a recovery media with your PC, don’t worry – you can download a Windows 7/Vista recovery disc that allows you to do the same thing with a retail disc – except reinstall Windows of course: see for Windows 7 and for Windows Vista. It’s in ISO format that you can easily burn to a disc.

Put the disc in, then as it comes up to the installation section (for retail discs), click “Repair my computer” then go and select your Windows installation, and from there select Command Prompt. For the recovery media discs you downloaded from NeoSmart – we’re not sure what the steps are, but it’s probably similar.

Then you need to type:

Note: execute one command at a time

bootrec.exe /FixBoot

bootrec.exe /FixMbr

It takes less than a second. Reboot and it’ll boot into Windows automatically. Then go to Start menu, right click Computer and select Manage. Go to Disk Management from here, and delete the partitions related to Ubuntu. Once you’ve done this, extend the volume size of your Windows partition to take the remaining free space. To delete/extend volume size of a partition, you right click.


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