A few year ago I built myself a NAS. It has a 320GB HDD for ubuntu OS and a 2TB HDD for files. I mounted de 2TB disk and shared it with samba over my network.

Now I have build a HTPC like system and want to put the 2TB disk in that system. This system runs windows 10. I doubted if I could simply connect it to my new system but tried just to see if it would work. It shows as unallocated space in the Windows disk manager so I figured I should just copy all the files to another disk, then format the 2TB disk in windows and copy all the files back.

Unfortunately I can't mount my 2TB disk anymore on my NAS. When I do fdisk -l is shows as a Microsoft Reserved Partition:

Disk /dev/sda: 1.8Tib, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: F7CB1168-49F7-4885-BFE2-EF9905099A86

Device    Start   End Sectors Size Type
/dev/sda1    34 32767   32734  16M Microsoft reserved

Partition 1 does not start on physical sector boundary.

EDIT 1: I opened the disk in gparted. According to gparted it has 16Mb partition with the next warning:

Unable to detect file system! Possible reasons are:
- The file system is dammaged
- The file system is unknown to GParted
- There is no file system available (unformatted)
- The device entry /dev/sda1 is missing

The other 1.82Tb shows as unallocated

EDIT2: my fstab shows:

# data disk
UUID=cfcf09cb-55-fc-40a7-b0b3-afd4d809bb09    /media/emiel/data        ext4    auto,user,rw      0      0

I am trying to mount the disk from the terminal for now.

EDIT 3: As per @Rusi's suggestion I tried parted rescue with no results:

emiel@ubuntu:~$ sudo parted /dev/sda print
Model: ATA WDC WD20EZRZ-00Z (scsi)
Disk /dev/sda: 2000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name                          Flags
 1      17.4kB  16.8MB  16.8MB               Microsoft reserved partition  msftres
emiel@ubuntu:~$ sudo sfdisk -d /dev/sda                                  
label: gpt
label-id: F7CB1168-49F7-4885-BFE2-EF9905099A86
device: /dev/sda
unit: sectors
first-lba: 34
last-lba: 3907029134

/dev/sda1 : start=          34, size=       32734, type=E3C9E316-0B5C-4DB8-817D-F92DF00215AE, uuid=58F98377-19F8-46D0-AF53-490D2987D76D, name="Microsoft reserved partition"
emiel@ubuntu:~$ sudo parted /dev/sda rescue
Start? 34                                                                 
End? 3907029134                                                           
searching for file systems... 100%      (time left 00:00)Information: You may need to update /etc/fstab.

EDIT 4: I tried gdisk as per @Rusi's suggestion with the next result:

emiel@ubuntu:~$ sudo gdisk /dev/sda
GPT fdisk (gdisk) version 1.0.3

The protective MBR's 0xEE partition is oversized! Auto-repairing.

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.

EDIT 5: After the above I tried TestDisk to scan my drive. It is still scanning but it outputs a lot of the same thing. Can someone explain to me what this means?

  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]
  Linux                    0   0  1 243201  80 63 3907029168 [data]

EDIT 6: Overnight the above (MBR) scan completed with the following result:

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>

Disk /dev/sda - 2000 GB / 1863 GiB - CHS 243201 255 63

The harddisk (2000 GB / 1863 GiB) seems too small! (< 2999 GB / 2793 GiB)
Check the harddisk size: HD jumpers settings, BIOS detection...

The following partition can't be recovered:
     Partition               Start        End    Size in sectors
>  Linux                121428 157 10 364629 238  9 3907029168 [data]

[ Continue ]
ext4 blocksize=4096 Large_file Sparse_SB Recover, 2000 GB / 1863 GiB

After I hit continue I wasn't able to browse files or do anything at all listed on the walkthrough. I could only 'quit'.

EDIT 7: But then I thought, maybe I should scan as "None" partition table, as suggested when I start testdisk, so I did:

Disk /dev/sdc - 2000 GB / 1863 GiB - CHS 243201 255 63
Current partition structure:
     Partition                  Start        End    Size in sectors

   P ext4                     0   0  1 243201  80 63 3907029168 [data]

This is exactly what is on my disk, an ext4 partition covering the whole disk named "data".

My conclusion: When I formated the disk 2+ year ago I did it wrong but did not notice, which resulted in a disk without a partition table. When I connected it to my Windows machine it found no partition table and created a wrong one. So I think I need to delete the partition table. I did search online but there is no information mentioning ONLY removing the partition table, not the existing partitions.

Another option would maybe be to create a correct partition table myself to point at the existing ext4 partition.

My question: Is my conclusion right? And can you advise me on how to accomplish above tasks?

  • It's not clear: Did you have a partition on the 2TB that has disappeared? May help if you show it's /etc/fstab – Rusi Mar 2 at 14:34
  • @Rusi The question is very clear, what is not clear is what is the OP expecting this group can advise about a disk that was obliterated by Windows disk manager – Rui F Ribeiro Mar 2 at 14:39
  • @Rusi it had one single ext4 partition – E. Brommer Mar 2 at 14:41
  • 1
    Just so I'm keeping track, you successfully formatted the drive with Windows? And you want to use the drive with Ubuntu? – Jeff Schaller Mar 2 at 14:44
  • 1
    Extremely unlikely Side note: I suggest you retitle and retag your question towards the need for rescuing a lost partition/filesystem – Rusi Mar 2 at 15:06

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