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-   -   error: unknown filesystem. grub rescue> (https://www.linuxquestions.org/questions/linux-newbie-8/error-unknown-filesystem-grub-rescue-880150/)

cynwied 05-11-2011 02:22 PM

error: unknown filesystem. grub rescue>
 
error: unknown filesystem
grub rescue>


My apologies for having to post, but after reading Similar Threads, and a few help tutorials, I just don't understand enough about the problem to correct it.

Background: My mother's HP laptop had Ubuntu and Vista on it, Ubuntu my brother's doing. He decided he wanted to take off Ubuntu yesterday (he had forgotten the password), and deleted the partition that it was contained within. The computer now boots to this error.

Inventory: We no longer have the install disk for Windows Vista, he cannot tell me what version he used of Ubuntu, what partition it was on, any of the specs for the machine, or generally any information about the system. All I am aware of is that error on the boot-up screen. I have nothing else to work with.

I would like to remove Grub, and Ubuntu, and leave Windows intact (the request of the owner of the computer), but I have no idea what commands I could use to get rid of either when I can't access Windows, or how to properly remove them if I did access Windows.

It's disappointing none of us here can use Ubuntu properly, as I'm told it's one of the best systems. But any help that could be offered would be appreciated.

markush 05-11-2011 02:51 PM

Hello cynwied, welcome to LQ,

the problem is that you'll have to boot a Windows-install-CD in order to let it fix the masterbootrecord.

What happened is simply that grub was (actually it is still) installed in the masterbootrecord of the harddisk. Grub was (is) configured to boot Windows and Ubuntu. If you remove Ubuntu you cannot use Grub anymore and so Vista will not boot.

What you can do (simplest solution) install Ubuntu again. If it is true that your brother only deleted the partition, you'll probably have only to create the partition again in the free space on the disk.
Note that the Partitiontable is only a table of contents, if only there a partition is deleted without creating a new one or formatting the partition all data are still there.

Do you have a Linux (Ubuntu)-install CD?

Markus

yancek 05-11-2011 05:25 PM

As markush indicates above, almost all the Grub boot files are on the partition your brother deleted.
If you want to restore the vista bootloader and don't have an installation CD, you should be able to do it with EasyBCD, particularly if your mother is strictly a windows user. Here's a link for the documentation:

http://neosmart.net/wiki/display/EBC...r+with+EasyBCD

Here's a link to the download:

http://neosmart.net/thankyou.php?app=EasyBCD

Or you could reinstall Ubuntu. If you choose this option, it would be best if you use the Ubuntu Live CD (if you have it run the command: sudo fdisk -l(lower case Letter L in the command) to get your partition information and post it here so someone can tell you which partition to use or how to create it so you don't overwrite windows.

cynwied 05-24-2011 12:06 AM

Quote:

Originally Posted by markush (Post 4353529)
What you can do (simplest solution) install Ubuntu again. If it is true that your brother only deleted the partition, you'll probably have only to create the partition again in the free space on the disk.
Note that the Partitiontable is only a table of contents, if only there a partition is deleted without creating a new one or formatting the partition all data are still there.

Do you have a Linux (Ubuntu)-install CD?

Markus

@Markus.
Thank you for taking the time to reply to this. He only deleted the partition, and he produced the disk, but even with the disk, it does not seem willing to reinstall Ubuntu. There are two scenario now presented upon booting.

Without Ubuntu disk:
Intel UNDI, PXE-2.0 (build 082)
For Realtek RTL8139(X)/8130/810X PCI Fast Ethernet Controller v2.13 (020326)
PXE-E61 : Media test failure, check cable
PXE-M0F : Exiting PXE ROM.
error : unknown filesystem
grub rescue>

With Ubuntu disk:
Some text flashes by too quick to read, and then lower-center screen shows what looks like a little keyboard symbol to the left, and a little person symbol to the right. There's another brief flash of cursor, though no visible text, and then the ubuntu logo with five loading red dots just stays up indefinitely, with no change.

What would be your suggestion on where to go from here? Is there a key command you press at one of the loading screens to enter part of the console, and force re-installation? Is it supposed to happen automatically?

cynwied 05-24-2011 12:12 AM

Quote:

Originally Posted by yancek (Post 4353685)
As markush indicates above, almost all the Grub boot files are on the partition your brother deleted.
If you want to restore the vista bootloader and don't have an installation CD, you should be able to do it with EasyBCD, particularly if your mother is strictly a windows user.

Or you could reinstall Ubuntu. If you choose this option, it would be best if you use the Ubuntu Live CD (if you have it run the command: sudo fdisk -l(lower case Letter L in the command) to get your partition information and post it here so someone can tell you which partition to use or how to create it so you don't overwrite windows.


From what I read of your link, it requires you to be able to boot onto one system or another. We have only black screen to work with, no options to select, very little text, no windows to pull up. It seems all three possibilities presented with the first link require some part of Windows to be booted. Which is odd and contradictory, so maybe I'm misunderstanding?

We have the Ubuntu install disk now, but how do you run the command? Where do you type it in? grub rescue> calls it an 'Unknown command', the text to get partition information. I feel your answer would likely be very helpful, but I can't seem to understand at which points to follow it through. Please see the above post for more information on what the computer is doing now, with and without disk.

yancek 05-24-2011 12:32 AM

You should be able to download a vista Recovery CD from this site if you don't have your vista installation CD. I would suggest reading the page completely before doing anything.

http://neosmart.net/wiki/display/EBC...r+from+the+DVD

The fdisk command won't work at a grub prompt. Try instead: ls (that's a lower case Letter L). Post that info here.

When you have the Ubuntu disk in the drive, do you have the CD set to first boot priority in the BIOS? Don't know why it wouldn't work if it worked before.

syg00 05-24-2011 12:38 AM

Using the first neosmart link above, read the blue box - that is your situation. Click the "our manual recovery instructions" - that will help you get a Vista recovery disk, and fix the MBR so Vista will boot natively.
You will need another machine to download the iso and burn it (as an image) so you can recover this machine.

Edit: too slow again .... good luck

cynwied 05-25-2011 09:32 PM

Quote:

Originally Posted by syg00 (Post 4365247)
Using the first neosmart link above, read the blue box - that is your situation. Click the "our manual recovery instructions" - that will help you get a Vista recovery disk, and fix the MBR so Vista will boot natively.
You will need another machine to download the iso and burn it (as an image) so you can recover this machine.

Edit: too slow again .... good luck

We followed this route first, and tried to follow the steps described within this link:
http://neosmart.net/wiki/display/EBC...r+from+the+DVD
The iso was burned to disk, it whirred within the drive, but no manner of F12 would get any command to come up. Simply:

error: unknown filesystem.
grub rescue>

So it was somehow supposed to circumvent grub and suppress it long enough to boot from the cd? To my knowledge there is nothing wrong (it has not been damaged or corrupted) with the Vista bootloader; grub simply comes first.

My continued thanks, however. This is going to take a lot of luck.

cynwied 05-25-2011 09:39 PM

Quote:

Originally Posted by yancek (Post 4365241)
You should be able to download a vista Recovery CD from this site if you don't have your vista installation CD. I would suggest reading the page completely before doing anything.

http://neosmart.net/wiki/display/EBC...r+from+the+DVD

The fdisk command won't work at a grub prompt. Try instead: ls (that's a lower case Letter L). Post that info here.

When you have the Ubuntu disk in the drive, do you have the CD set to first boot priority in the BIOS? Don't know why it wouldn't work if it worked before.

Written above was the results of trying to get it to recognize the Vista Recovery CD. It keeps talking about a command prompt on the Neosmart page, but we've never gotten any other screen to come up (that allows you to interact with it) then the grub rescue one.

ls prompt:

(hd0) (hd0,5) (hd0,1)

The person who originally installed Ubuntu couldn't answer your question. So, fantastic question: How do you set a CD's priority to first boot? Because that would allow either solution presented by posters to work.

Thank you for continued patience.

segmentation_fault 05-25-2011 10:27 PM

The boot priority can be set from the BIOS. When you power up your pc you can enter the BIOS by pressing F2 (usually on laptops) or delete (usually on tower PCs).
On the very first screen you should see something like <F2 Setup>
Then look for something like "Boot order" or "Boot device priority" or similar.

cynwied 06-01-2011 10:29 AM

Quote:

Originally Posted by segmentation_fault (Post 4367182)
The boot priority can be set from the BIOS. When you power up your pc you can enter the BIOS by pressing F2 (usually on laptops) or delete (usually on tower PCs).
On the very first screen you should see something like <F2 Setup>
Then look for something like "Boot order" or "Boot device priority" or similar.

Success. Thank you. Ubuntu has been reinstated and the computer runs again like it did.

Thank you to everyone who contributed, and were able to give instructions on how to correct this issue.


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