I recently bought a 3TB internal HDD, intended to be used as a backup drive to encompass all of my data. After installing the drive into my system, I started to use Windows' command-line diskpart tool to initialise it, as part of which it needed converting to a GPT disk. Eventually after some experimenting, I realised that doing so, using:

convert GPT

...automatically creates a 128MB reserved partition on the disk:

enter image description here

Why does diskpart create this partition, and if I'm planning to use this disk purely as a data drive (as opposed to a boot drive), can I safely delete the reserved partition to create one primary partition encompassing the entire drive?


"A Microsoft Reserved Partition is only created when a drive formatted in a Globally Unique IDentifier or GUID partition table (GPT) format and when the BIOS is set for Unified Extensible Firmware Interface (UEFI)."


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    The question was why is it created and can you get rid of it. Simply stating that it gets created does not answer the question. – psusi May 1 '18 at 18:14
  • That source partially answers the question of why, i.e. as part of a Windows installation on a GPT drive, but it doesn't address the question of why it is created for a standard data drive or whether it's needed on one. – Prometheus May 1 '18 at 19:38
  • @psusi this is the question "Why does converting a disk to GPT with diskpart automatically create a 128MB reserved partion?" Getting rid of it would be a duplicate question. – Moab May 1 '18 at 20:33
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    @Moab That's the title of the question because it can't contain the whole question - the rest of the question is in the body, and isn't a duplicate of any other, because no other question asks the same; whether deleting the reserved partition created by convert GPT can be safely deleted for a data drive. – Prometheus May 2 '18 at 18:18

This is not an answer to the question, but valuable information for anyone coming across this and wanting to know how to delete the partition, which is protected by default.

To delete the 128MB reserved partition

Type the following commands one at a time in the command-line:


list partition

select partition 1

delete partition override

To create a new primary partition encompassing the entire drive and mount it:

create partition primary

format fs=ntfs quick1

assign letter=D2

1 Replace ntfs with the filesystem you want to format the disk with, and remove quick if you want to perform a full format
2 Replace D with the volume label that you want the drive to be mounted on, or simply use assign to mount the drive with a random unused label

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