Recovering a Seagate Desktop Expansion disk

How to use TestDisk to recover lost partition
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rbailin
Posts: 1
Joined: 25 Oct 2021, 23:04

Recovering a Seagate Desktop Expansion disk

#1 Post by rbailin »

I'm helping a friend recover the contents of a 4TB Seagate Desktop Expansion disk whose enclosure pcb failed.

The physical drive still works, but this was one of those enclosures that translated 512e to 4096 sector sizes.

When I plugged the GPT layout drive into a SATA port, testdisk detected the correct partition format immediately. I wrote the partion table to the disk and rebooted, but Win10 did not regconize the partition table. Further analysis by testdisk showed the common error of mismatched sector sizes: 4096 in NTFS, 512 for the hard disk (HD). Crystal Disk Info confirmed that the sector size of the SATA disk is 512.

So I bought a USB 3.0 external enclosure (Orico), thinking that it would translate the 512e drive into a 4096 drive like the Seagate enclosure did. However, after putting the drive into the enclosure and deliberately plugging it inUAto a USB 2.0 port (to avoid possible problems with UASP optimization on a 3.0 port), it still comes up the the sector size error message. I've tried changing the disk geometry to a 4096 sector size, which reduces both the starting sector and total number of sectors, obviously. The partition remains readable, but I'm reluctant to write out the new partition table with the 4096 geometry without knowing whether the enclosure is actually presenting the drive with a 4096 sector size. Crystal Disk Info does not show the sector size when the disk is in the enclosure. I don't want to risk damaging the beginning of the single NTFS partition that occupies the entire disk.

I've done several successful limited test copies to disk from testdisk, and the files (mostly photos) appear to be correct, whether the sector size is set to 512 or 4096. No errors during the copy process.

I'm resigned to playing it safe, buying a new 6TB external USB drive and copying over everything from within testdisk.

What I'd like to know if there's a utility to definitively tell me how an external drive is presented to Windows. The closest I've come is Gsmart Control, which reports 512 logical / 4096 physical for the drive while it's in the USB enclosure. And I'm not really sure how to interpret that.

recuperation
Posts: 2721
Joined: 04 Jan 2019, 09:48
Location: Hannover, Deutschland (Germany, Allemagne)

Re: Recovering a Seagate Desktop Expansion disk

#2 Post by recuperation »

rbailin wrote: 26 Oct 2021, 02:11
What I'd like to know if there's a utility to definitively tell me how an external drive is presented to Windows. The closest I've come is Gsmart Control, which reports 512 logical / 4096 physical for the drive while it's in the USB enclosure. And I'm not really sure how to interpret that.
4096 bytes physical (real!) internally disguised as 512 bytes externally (emulated by the drive).

Read here:
https://www.seagate.com/tech-insights/a ... master-ti/

But - I consider the proclaimed gain in "efficiency" as a loss in error protection because the so-called "gain" comes at the cost of error correction information!

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