Grub Blues

How to use TestDisk to recover lost partition
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tweakster
Posts: 2
Joined: 01 Oct 2012, 00:02

Grub Blues

#1 Post by tweakster » 01 Oct 2012, 01:49

Hi. I was using Grub for dual booting into Windows and Linux. I decided to change the Linux OS and attempted to install by just overwriting the existing Linux OS, which in most cases should work fine. Well, as luck would have it, it did not go as planned. :o The old Linux got hosed and the new one failed to install. I was still able to boot Windows, but I had to get Grub out of the MBR before trying to install another Linux. When I used the instructions found on some MS websites for using Windows Recovery Console in accordance with my affected version (Windows 2000 Pro), it ended up trashing the MBR and partition table. Now even Windows would not boot. All it showed me was "Invalid Partition Table." I was fit to be tied. :evil: I think I also came up with some new words too. :P

Of course I had a recent backup, but that would put me back to the same spot since I had in fact carefully followed all instructions already. Then I recalled :idea: seeing a comprehensive set of recovery programs and utilities called Parted Magic, which looked wonderful when I originally found it but never had occassion to use. Well, this appeared to be a good time to take another look at. Sure enough, I noticed your program called TestDisk. At first the name of it threw me off because it sounded more like a hardware test or disk surface testing thingy. But for some reason I thought to give it a closer look. :cry: When I fired it up, I could see that it was all about the same kind of problem I was facing. I was starting to feel lucky at that point. 8-)

I came to your website to see if there was additional information about it, and the example and tutorial on how to use it was just about as close to my problem as I could have wished for. I followed it and presto! Just like magic, your program got me where I wanted to be. MBR scrubbed, Windows booted and old partitions gone away! I was elated. Thanks for that. :geek:

Now I have two questions in connection with this program. Firstly, while I followed the step-by-step guide on your website, I eventually got to the part for "Partition table recovery", and it happened just as described. Even so, the next part of your guide, which is labeled as "NTFS Boot sector recovery", seemed to suggest that I would have to follow some more steps before getting to the point of having to reboot. However, I don't believe my procedure showed me a part related to the boot sector recovery, but instead it jumped right to the part about rebooting. When I then rebooted, I was absolutely delighted by the sight of Win2K logon screen, just as I had left it. (I hope never to take it for granted again.) :lol:

Secondly, now that I have recovered my system and have a good MBR, does your program have a feature that allows me to back it up and restore it in the future if need be, as well as the boot sector of the NTFS partition? Thanks.

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Fiona
Posts: 2836
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: Grub Blues

#2 Post by Fiona » 01 Oct 2012, 11:46

Firstly, while I followed the step-by-step guide on your website, I eventually got to the part for "Partition table recovery", and it happened just as described. Even so, the next part of your guide, which is labeled as "NTFS Boot sector recovery", seemed to suggest that I would have to follow some more steps before getting to the point of having to reboot.
MBR is the first physically executable sector of the disk.
It also contains the partition table and determines your partitions and which one is bootable
Boot sector is the first logically executable sector of a partition.
If your boot sector is faulty or damaged, TestDisk looks for the backup of your boot sector and offers to write the backup of the boot sector over the boot sector.
Your boot sector will be repaired.
The size of your boot sector is 512 byte.
That's why it's a pretty fast action to repair it.
TestDisk / Advanced offers the oppertunity if the boot sector and the backup is broken, you can have a try to rebuild it.
It may take a bit longer.
Secondly, now that I have recovered my system and have a good MBR, does your program have a feature that allows me to back it up and restore it in the future if need be, as well as the boot sector of the NTFS partition? Thanks.
You only can backup and restore your partition table using TestDisk.
If you confirm at Analyse you can use the option Backup.
This creates a little text-file as a backup of your partition table in your testdisk folder.
Confirming at "Quick Search" displays the option L to load your backup and write it to your partition table.

MBR code is different.
TestDisk offers this option also.
It contains your boot loader and signatur that your MBR is valid.
Some Infos about it here;
http://www.cgsecurity.org/wiki/Menu_MBRCode

Fiona

tweakster
Posts: 2
Joined: 01 Oct 2012, 00:02

Re: Grub Blues

#3 Post by tweakster » 05 Oct 2012, 02:51

Hi, Fiona. I appreciated your taking the time to reply as thoroughly as you did. Now I have a question about using the functionality you mentioned for backing and restoring "...little text-file as a backup of your partition table in your testdisk folder." It is likely that I would be running TestDisk in a ISO RAM-loaded environment instead of from disk because the disk might not be accessible for loading an OS. Therefore, it would be necessary for me to have the ability to access a separate disk on which to store a backup and later recover it for rewriting on the damaged disk.

Now, if I were running the program from PartedMagic's ISO, its environment does include other programs with the ability to read and write to separate offline (i.e., inactive) disks and partitions, but the problem would be whether I could then tell TestDisk to use a specific file in this manner in place of its wanting to use a file in "your testdisk folder."

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