I have an external HDD connected via USB-3 that I can't get Diskpart to clean. It's a drive I robbed from my XP machine that was used as a backup. I just moved it from a USB-2 enclosure to a USB-3 enclosure. It has an "OEM Partition" that I can't delete. I was about to ask about it and ran across this thread. Is this a limitation of Diskpart on external drives?
That drive might be configured to have a DCO (drive configuration overlay) area in its firmware for the OEM partition to live in, essentially making it inaccessible except by custom software - that's my guess.
You would need a low-level HDD tool to reset this DCO and restore the drive to its native full capacity.
Just a quick follow up - The HP utility didn't work for me. It returned a "Locked Drive" error so I tried this one:
Download HDD Low Level Format Tool 4.12 Free - Utility for low-level hard disk drive formatting - Softpedia
It worked like a champ and I was able to get the full drive capacity back using Windows Format Wizard. I took a screen shot after it finished. It was quick--Less than a second.
I'm not sure what they mean in this case by low level formatting. I thought the ability to truly do low level formatting wasn't possible with modern disks?? I thought it was done during manufacture.
(this is a question by the way).
It's not really a "true low level format" but it does initialize the disk. There is an option in the HDDGURU program I used to specify the sector size but I choose Default and selected the Quick Wipe (lower right check box) that just clears the MBR and partitions. And it worked on the drive connected via USB. It basically put it back to factory form.
Good to know what to do in case of other persistent and specific problems. Thanks carwiz.
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