External drive vanished

How to use TestDisk to recover lost partition
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flash68
Posts: 11
Joined: 10 May 2012, 12:06

External drive vanished

#1 Postby flash68 » 10 May 2012, 12:17

Hi - My 1TB external drive suddenly vanished this morning (WinXP) (was not removed or powered off).
It disappeared from Windows Explorer and Disk Management showed it as:

Disk 2, Basic 931.51GB Online
With a single primary partition: 931.51GB Healthy (GPT Protected partition).

No drive letter is associated with it.

I know that previously (when it was working), this showed a small partition before the main partition - but I can`t remember what it was.

I`ve run Testdisk and it shows the following...

Disk /dev/sdc - 1000 GB / 931 GiB - CHS 969010 32 63
Current partition structure:
Partition Start End Size in sectors

1 P EFI System 40 409639 409600
Warning: number of heads/cylinder mismatches 255 (NTFS) != 32 (HD)
2 P MS Data 409640 1953262983 1952853344 [Time Machine]

TD lists the files on the main partition correctly but when I write the partition and reboot it still does not show.

I`d appreciate any advice with this. Thanks.

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Fiona
Posts: 2839
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: External drive vanished

#2 Postby Fiona » 10 May 2012, 12:56

Your disk is still listed as basic and not as GPT.
That's why you can't write a GPT-partition successfully.
Has your external disk been a GPT or a basic disk?
You can convert your disk to gpt and repeat your diagnose using testdisk.
It probably might be ok to diagnose after converting only your boot sector?
But it requires a diagnose to determine it.
Important at the moment, do you know what disk type did you have?
GPT or basic?

Fiona

flash68
Posts: 11
Joined: 10 May 2012, 12:06

Re: External drive vanished

#3 Postby flash68 » 10 May 2012, 13:19

Thanks Fiona - I'm not sure to be honest.
It was originally bought for a Mac to be used as a time-machine backup drive (hence the title). When my Mac died I formatted for PC it using Macdrive 9 as NTFS but I'm not sure whether it was Basic of GPT. Does the way I formatted it tell you which it is? (sorry not too sure of these things). It has been used on Windows for some time.
If I convert to GPT, will I lose my files? If not, how do I do it?
Disk management popped up with a wizard asking me to initialize another drive (an internal hard drive that vanished at the same time - this is also an ex-Mac drive and was blank so I'm not worried about that, but still strange. This is showing as Basic and unallocated).

flash68
Posts: 11
Joined: 10 May 2012, 12:06

Re: External drive vanished

#4 Postby flash68 » 10 May 2012, 17:04

Can anyone help please.. I can see my files with Testdisk, I just dont know how to change the partitions to access the drive again.

Thinking about the reply I gave to Fiona, I seem to remember originally there was a very small GPT partition at the start, then the large (almost 1GB) NTFS partition, then another very small partition at the end, now there is just the 1 large GPT partition - does this make sense?

Any ideas?

User avatar
Fiona
Posts: 2839
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: External drive vanished

#5 Postby Fiona » 10 May 2012, 17:39

A suggestion would be that you repeat your diagnose.
In TestDisk, after disk selection you come to the partition table types.
Please choose Intel instead of EFI GPT and repeat your diagnose.
I'd need infos from Analyse, Quick Search and in case if nothing was found from Deeper Search.
It might be possible to write an intel partition table to get access to your data of your partitions.

Fiona

flash68
Posts: 11
Joined: 10 May 2012, 12:06

Re: External drive vanished

#6 Postby flash68 » 11 May 2012, 20:22

Hi Fiona - here are the details you suggested...
Does this tell you what has happened and how I can fix it.
Thanks

From Analyse: Intel/PC
----------------------

TestDisk 6.14-WIP, Data Recovery Utility, May 2012
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdc - 1000 GB / 931 GiB - CHS 121601 255 63
Current partition structure:
Partition Start End Size in sectors

1 P EFI GPT 0 0 2 121601 80 63 1953525167
No partition is bootable

---------------------------------------------------------------------------
From Quicksearch:
-----------------

TestDisk 6.14-WIP, Data Recovery Utility, May 2012
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdc - 1000 GB / 931 GiB - CHS 969010 32 63
Analyse cylinder 116937/969009: 12%8


check_FAT: can't read FAT boot sector
Invalid FAT boot sector
0 D FAT12 1864826 9 6 2533691 23 19 1348432736
FAT12 1864826 9 6 2533691 23 19 1348432736

---------------------------------

From Quicksearch / Deeper search:
---------------------------------

TestDisk 6.14-WIP, Data Recovery Utility, May 2012
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdc - 1000 GB / 931 GiB - CHS 121601 255 63

The harddisk (1000 GB / 931 GiB) seems too small! (< 2615 GB / 2435 GiB)
Check the harddisk size: HD jumpers settings, BIOS detection...

The following partition can't be recovered:
Partition Start End Size in sectors
> FAT12 234017 106 6 317953 120 19 1348432736

[ Continue ]
690 GB / 642 GiB

User avatar
Fiona
Posts: 2839
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: External drive vanished

#7 Postby Fiona » 11 May 2012, 20:28

The following partition can't be recovered:
Partition Start End Size in sectors
> FAT12 234017 106 6 317953 120 19 1348432736

[ Continue ]

This is only a message that your partition ends after disk limit and can't be recovered.
It has no significance because Testdisk can recognize partitions on the basis of remnants.
What happens if you press enter to continue.
You'll come to the result of Quick Search.

Fiona

flash68
Posts: 11
Joined: 10 May 2012, 12:06

Re: External drive vanished

#8 Postby flash68 » 11 May 2012, 20:52

If I press Continue, I get the following...

TestDisk 6.14-WIP, Data Recovery Utility, May 2012
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdc - 1000 GB / 931 GiB - CHS 121601 255 63
Partition Start End Size in sectors

No partition found or selected for recovery

flash68
Posts: 11
Joined: 10 May 2012, 12:06

Re: External drive vanished

#9 Postby flash68 » 11 May 2012, 22:51

When I analyse as GPT, I get the following. And the files can be seen under the main partition.

TestDisk 6.14-WIP, Data Recovery Utility, May 2012
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdd - 1000 GB / 931 GiB - CHS 121601 255 63
Partition Start End Size in sectors
>P EFI System 40 409639 409600 [EFI]
P MS Data 409640 1953262983 1952853344 [Time Machine]

flash68
Posts: 11
Joined: 10 May 2012, 12:06

Re: External drive vanished

#10 Postby flash68 » 11 May 2012, 23:10

Deeper search as GPT gives this...

TestDisk 6.14-WIP, Data Recovery Utility, May 2012
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdd - 1000 GB / 931 GiB - CHS 121601 255 63
Analyse cylinder 196/121600: 00%


check_FAT: Unusual media descriptor (0xf0!=0xf8)
Warning: number of heads/cylinder mismatches 16 (FAT) != 255 (HD)
Warning: number of sectors per track mismatches 32 (FAT) != 63 (HD)
EFI System 40 409639 409600 [EFI]
check_FAT: Unusual media descriptor (0xf0!=0xf8)
Warning: number of heads/cylinder mismatches 16 (FAT) != 255 (HD)
Warning: number of sectors per track mismatches 32 (FAT) != 63 (HD)
EFI System 46 409645 409600 [EFI]
Mac HFS 64474 125913 61440
Mac HFS 3038 64477 61440
MS Data 409640 1953262983 1952853344 [Time Machine]


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