Member Avatar for mah300274

I took the hdd out of my external computer to transfer a large # of files (over 1TB worth) and to use the full 3tb I made it a GPT Partition. Now since I want it back in the normal enclosure the computer "sees" it, in the device manager or a partition manager, but they say it is a MBR and needs formatted? I am assuming it has to to with the sata to usb converter in with the enclosure. I just would like to see the 'old' record with the gpt partition of 3TB's.

Thanks.

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Generated

Short summary and the safe next steps.

Cheap or older USB–SATA bridge firmware often hides or changes how a disk’s partition table and LBA size are reported. A GPT disk includes a protective MBR (partition type 0xEE) and relies on 48‑bit LBA for disks >2.2 TB; if the enclosure/bridge or the host OS doesn’t handle that correctly the volume can appear “unknown/MBR” and Windows will prompt to initialize or format. This explains why ’s drive worked when moved to a Linux box (Linux + a direct SATA path usually exposes the real GPT and full size).

Do not initialize or format the disk in Windows. Safe inspection steps you can run without writing to the disk:

# Windows (run as Administrator)
diskpart
list disk    # look for a "*" under the GPT column for the disk

# Linux (live USB is ideal)
sudo parted -l
sudo fdisk -l /dev/sdX   # replace sdX with your device

If the disk shows the correct full capacity and a GPT flag on a direct SATA connection, the problem is the USB enclosure. If the partition table looks missing or corrupted even on SATA, image the disk first, then try recovery tools.

Recovery options and precautions

  • Image the disk before any repair (critical data): a quick read-only header capture is useful:
    sudo dd if=/dev/sdX of=~/disk-start.img bs=512 count=2048

    (this saves the first ~1 MiB; for full recovery consider ddrescue or a full image).

  • If the disk is intact but hidden by the bridge, move it to an internal SATA port or use a modern USB3 adapter/enclosure that explicitly supports >2.2TB and GPT/48‑bit LBA.
  • If the GPT headers were damaged, use recovery tools (TestDisk or GPT fdisk/gdisk) from Linux to inspect and, if appropriate, restore the GPT from its backup header — but only after imaging the drive.

Tie-in to earlier replies

was right to flag partition-type/OS compatibility as the root cause; the symptom of being prompted to format is exactly what happens when the host can’t interpret the on-disk partitioning. For long-term use of >2TB drives keep them either on a controller known to support 48‑bit LBA/GPT or in an external enclosure that lists support for 3TB+ drives.

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Member Avatar for techsheaven

Maybe you should start from the beginning and give more information... IF it had an MBR, it WAS a system drive. If you changed the partition type, the old data may no longer be accessible. Not all Partition types are supported by all Operating Systems. If you are being prompted to format the drive, then the formatting is not recognized by the System.

Post back here with some details, and hopefully we can get you taken care of.

Member Avatar for mah300274

I think I had figured it out, the device wanted to be the main controller for the card, so when it had a different partition table as the drive, it wanted to read as non-partitioned, but when both were the same, the device was recognized. But anyway, I just added the drive to my simple ubuntu server since my router apparently has issues with 2TB+ (some people had success but some don't)

Member Avatar for caperjack

I took the hdd out of my external computer

i first read this thread 5 days ago[had no answer ] and im still trying to figure out what a external computer is ,lol

Edited by caperjack because: n/a
Member Avatar for mah300274

I did not even notice that lol, but hopefully most knew what I was saying, I will just mark this thread as solved...

Member Avatar for caperjack

I
but hopefully most knew what I was saying, .

yeah ,not everyone is as dense as I

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