Recover single partition without losing others

[thecoldheartofspac]

I dual booted with linux mint 13 a while ago on my grandma's computer that had vista. I decided that since vista crashes so much and is nearly unusable, I'd install xp. I got everything ready with gparted, but when I installed xp, it corrupted the linux partition. I had some important data on there and found testdisk which I started, but I don't get how to recover only that single partition. If anyone could help, I'd be very great full! Thanks!

[oldfred]

Did Windows do like usual and make a partition in the extended partition disappear. Or worse did you overwrite the Linux partition.
Windows does not correctly see Linux partitions and during install it rewrites partition table often forgetting to include the linux partition.

Testdisk will show many or all old versions of partition table. Best if you know where on drive and approxite size. Actual best is fdisk output or Boot-Info report from before to know exact sectors.
If you have empty space in an extended partition that probably was your Linux partition. Testdisk should let you just recover that, but do not change status of other partitions.

Best to backup current partition table and post details here as another backup.
Backup partition table to text file & save to external device.
sudo sfdisk -d /dev/sda > PTsda.txt

Also post the contents of PTsda.txt in code tags. You can use # icon in advanced editor to add code tags around highlighted text.
Also post this:
sudo parted /dev/sda unit s print

[thecoldheartofspac]

Thanks for the quick reply! Ya. the main sections of the enxtended partition is "unallocated" but the rest is fine. With the first command #sudo sfdisk -d /dev/sda > PTsda.txt# I got #Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently# on the second
#Number Start End Size Type File system Flags
1 63s 112454s 112392s primary fat16 diag
2 112640s 66555903s 66443264s primary ntfs boot
3 66555904s 185708543s 119152640s primary ntfs
4 185708544s 488280063s 302571520s extended
5 185710592s 202147839s 16437248s logical ext4
6 486207488s 488280063s 2072576s logical linux-swap(v1)"

in testdisk I got
#Disk /dev/sda - 250 GB / 232 GiB - CHS 30395 255 63#

Partition Start End Size in sectors

1 * FAT16 >32M 0 1 1 6 254 63 112392 [DellUtility]
2 P FAT32 LBA 7 0 1 4184 254 63 67119570 [NO NAME]
3 P Linux 11559 242 12 12583 30 55 16437248 [otherinstall]
4 E extended LBA 12583 31 1 30394 254 63 286147827
5 L Linux 12583 63 25 30264 226 42 284055552 [mint13] <---- the one I want to recover
6 L Linux Swap 30265 4 12 30394 6 60 2072560#

I don't get entirely how to use testdisk, so any help that can be given there would be greatly appreciated as opposed to me experimenting and destroying it all. Thanks!

[nerdtron]

I don't think you messed up your partitions. Windows XP just blew GRUB away. You can still access you data once you boot from a LIVE CD.
Or a better solution would be to restore GRUB.

[thecoldheartofspac]

I've checked it with gparted and every partition is fine. Xp and vista both boot fine through grub. I would show you a screenshot, but I don't know how to save it to the disk to upload. I'm typing this and all other messages from a smartphone so I can't really show you anything but text.
I'm only 15, and I usually learn about linux one or two topics at a time in different sections as my computer and others I fix have problems or break. This is the fist time I have had a single partition with important info corrupted without being overwritten and other thing I need to keep intact, so it's my first time learning about this program. Thanks for the guess though :)

[oldfred]

Ignore cylinder boundry error. That was for old IDE drives years ago.

I am having a bit of an issue with the differnece between the fdisk and testdisk output. Testdisk does use the old CHS - cylinders, heads, sectors which are not really used any more.
Fdisk shows your extended sda4 with a current sda5 as a Linux ext4, then a gap (missing partition?) and then sda6 your swap.
But testdisk is not showing that. It has an extended, with just one ext4 labeled as Mint13 and swap inside the extended. Normally a deleted partition had a D and you have to change to L or P for logical or primary. All logical partitions must be in one extended partition.
Did you have two Linux partitions in your extended or one large one and the current small one is not correct?
Have you tried deeper search in testdisk?

Guide to Forum features ** INCLUDES: Beans, titles, searching, and more
http://ubuntuforums.org/showthread.php?t=1006656
How to attach file, screenshots
http://ubuntuforums.org/showpost.php?p=12229098&postcount=4
http://i.stack.imgur.com/0E6qS.png

[thecoldheartofspac]

The one that says "otherinstall" is the other linux partition. It's just where I plan to put any OS I want to experiment with. I haven't tried deeper search, but I have found everything I need to. Here's the picture of gparted and testdisk. Hopefully it clears up what I've been trying to say. The unpartitioned part is where my main linux should be. everything else should stay intact. Thanks for the link showing how to upload photos ;) For some reason I couldn't see it on my computer untill I used firefox.

[oldfred]

Your testdisk does not show any NTFS partitions and has otherinstall as primary. But your current gparted shows otherinstall as logical and the space that is you mint as unallocated. Usually testdist shows all the old combinations of partitions and you have to pick & choose a set that is correct and does not overlap.

Since it is only one partition I might just try gparted's recovery or parted's rescue. I think gparted is doing the same thing as parted (gparted is really the gui for parted).

GParted's partition-recovery tool.
Device -> Attempt Data Rescue in GParted


http://www.gnu.org/software/parted/manual/html_node/rescue.html

Use parted rescue to restore missing partition details in post #22
http://ubuntuforums.org/showthread.php?t=1775331

[thecoldheartofspac]

Okay. I just tried to use parted, but when the first part didn't work, I tried doing
check 4 and I got
Error: Partition /dev/sda4 is being used. You must unmount it before you modify it with Parted I checked and the hdd isn't mounted. If gparted is based on parted, I'd guess that's why it didn't do anything either the first time I tried.

[oldfred]

If swap is in extended partition the live system mounts swap to speed up processing and that in effect mounts the entire extended partition.
You need to swap off on swap. Click on swap and right click.

[thecoldheartofspac]

okay, I did that with parted, but then instead, it started trying to use the cd instead of the hdd. Also, I got testdisk mostly working and mostly figured out, but now, it won't let me bring back all my wanted partitions. That's the picture on the attachments. I see that "D" means delete, and the rest are various options, but it will only let me select a few at a time. I think that it's not counting the extended partition as extended, because it only allows for 4 to come back. Is there a way to make this detect that the linux partitions are in extended?

[oldfred]

You do not explicitly set the extended. Put both linux and the swap as logical as it will make a correct extended.
All logical have to be next to each other so they all can be in one extended partition.
You can only have 4 primary and the extended counts as one of the primary.
So you should specify 3 primary and the rest as logical.
None of the choices can overlap as you show 3 starting about at 7 and going to 4142, so only one of those three can be selected. Choose the correct one probably OS but I do not know for sure.