2

I have an internal 3 terabyte WD Black disk that was set up as GPT (presumably?) and formatted with one NTFS partition spanning the entire disk under Windows 7.

After upgrading to Windows 10, the other disks in the system were recognized without issue (including a 3-disk raid!) but this disk did not get mapped and shows up in Disk Management with a two terabyte GPT Protective Partition and 700-some gigabytes of unallocated space.

The motherboard in this machine is an Asus M4A78 Plus from around 2009, so it's pre-UEFI but I'm not attempting to boot from this disk so that shouldn't be the issue.

I've pulled the drive and put it into my Linux machine, where fdisk says:

Disk /dev/sdd: 3000.6 GB, 3000592982016 bytes, 5860533168 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
Disk identifier: 0x59e095e7

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1  4294967295  2147483647+  ee  GPT
Partition 1 does not start on physical sector boundary.

It might be related to the 512 byte logical sector size? I've other people having similar issues with Macs and boot camp or external drives being used internally but this disk had been set up internally on Windows and worked fine until I moved to Windows 10.

I haven't seen anyone with this specific issue yet so I figured I'd ask here and see if anyone has any ideas. The disk has about 2tb of data that isn't backed up (I should know better!) so I'm hoping to keep that.

gdisk output (device name changed):

GPT fdisk (gdisk) version 0.8.10

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

Creating new GPT entries.

Command (? for help): v

No problems found. 5860533101 free sectors (2.7 TiB) available in 1
segments, the largest of which is 5860533101 (2.7 TiB) in size.

Command (? for help): p
Disk /dev/sde: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 50176CDA-0B0F-4D2E-9459-687BCF80AF4E
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 5860533101 sectors (2.7 TiB)

Number  Start (sector)    End (sector)  Size       Code  Name

Command (? for help):
Improve this question
3
  • Your sector sizes aren't an issue. What does sgdisk -v /dev/sdd tell you? That will run GPT-specific integrity checks on the disk data structures. One thing I notice, which is a long shot, is that your disk has an MBR disk identifier of 0x59e095e7; but the GPT spec says this field should be empty. If you find no other problems, you could try zeroing this out. The easiest way might be to use the n option on gdisk's experts' menu (x, then n, then w). This actually creates an entirely new protective MBR. You can also back up the disk from Linux, assuming Linux sees your partitions.
    – Rod Smith
    Commented Aug 5, 2015 at 23:42
  • It tells me: Creating new GPT entries. No problems found. 5860533101 free sectors (2.7 TiB) available in 1 segments, the largest of which is 5860533101 (2.7 TiB) in size.
    – pent
    Commented Aug 6, 2015 at 14:12
  • The Creating new GPT entries message suggests that sgdisk thinks the disk is unpartitioned. Try using sgdisk -- launch it on the disk and then type v and then p. Post the output. (Edit your original question and add four spaces to the start of each line of output, or put it up on a pastebin site.)
    – Rod Smith
    Commented Aug 6, 2015 at 19:56

0

Reset to default

You must log in to answer this question.

Browse other questions tagged .