GParted says hard drive is "unallocated"

[oldfred]

Left off the install

sudo apt-get install testdisk

[Cipher1874]

Alright, that's done. So now I turn off my laptop and go into BIOS to check if it's UEFI?

Also, I went ahead and tried the backup process in the link for repairing GPT, but when I typed in sgdisk -b sda-backup.gpt /dev/sda, I get the following message: Problem opening /dev/sda for reading! Error is 13.
You must run this program as root or use sudo!

[oldfred]

If you are booting liveCD or USB, the programs you just installed will not be saved. You have to reinstall each time you boot CD as CD is not writeable. You can change some settings on USB flash installer to save some data with a persistent setting.

I do not know what error 13 is. Try with sudo. But if gparted said table was bad then even gdisk may also see the errors and have problems trying to back up damaged data.

What does testdisk show?

[Cipher1874]

xubuntu@xubuntu:~$ sudo sgdisk -b sda-backup.gpt /dev/sda
Caution! After loading partitions, the CRC doesn't check out!
Warning! One or more CRCs don't match. You should repair the disk!

************************************************** **************************
Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk
verification and recovery are STRONGLY recommended.
************************************************** **************************

Warning! Secondary partition table overlaps the last partition by
33 blocks!
You will need to delete this partition or resize it in another utility.
The operation has completed successfully.

How do I open testdisk? Sudo? So it'd just be sudo testdisk?

[oldfred]

Yes sudo testdisk should work?

How did partitions get changed? Did you run some utility or installer somewhere?

[Cipher1874]

Alright, I'll run that right now. It shows:

TestDisk 6.13, Data Recovery Utility, November 2011
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org


TestDisk is free data recovery software designed to help recover lost
partitions and/or make non-booting disks bootable again when these symptoms
are caused by faulty software, certain types of viruses or human error.
It can also be used to repair some filesystem errors.

Information gathered during TestDisk use can be recorded for later
review. If you choose to create the text file, testdisk.log , it
will contain TestDisk options, technical information and various
outputs; including any folder/file names TestDisk was used to find and
list onscreen.

Use arrow keys to select, then press Enter key:
>[ Create ] Create a new log file
[ Append ] Append information to log file
[ No Log ] Don't record anything

Do I select create or append?

And no, I don't really know anything about that, so I have no idea how to change partitions.

[oldfred]

Log file is in case you want to know what happened. Not sure if it offers anything else or not. I usually check no log file.

[Cipher1874]

Alright, I clicked intel / pc and then I click analyse?

When I do, it says this:

Disk /dev/sda - 500 GB / 465 GiB - CHS 60801 255 63
Current partition structure:
Partition Start End Size in sectors

1 P EFI GPT 0 0 2 267349 89 4 4294967295

Warning: Bad ending head (CHS and LBA don't match)
No partition is bootable

[oldfred]

It also is seeing it as gpt. Try the gpt or second entry.

[Cipher1874]

You mean this link, right?
http://www.rodsbooks.com/gdisk/repairing.html

The problem is, I still can't back it up using the command given in bold.