partitioning - How to create an additional GUID partition on a GPT disk, using Diskpart, in Windows 10?

I have Windows 10 installed on on a GPT disk. This is the current partition layout:

• Partition 1: 499 MB (Recovery)


• Partition 2: 99 MB (System)


• Partition 3: 16 MB (MSR)


• Partition 4: 320 GB (Primary - drive letter C:)


• Unallocated Space: 610 GB

What is the right way to create an additional GUID partition, to fill the unused 610 GB? Preferably using the DiskPart command line utility.

There is plenty of material on the internet on converting MBR disks to GPT, but I'm struggling to find a simple example of how to add another GUID partition to unallocated space on an existing GPT disk.

I'm also confused about what GUID partition "ID" is required to create a normal partition that I can format and mount as drive D: like I used to back in the old-school MBR days.

Thanks for your help!

Answer

but I'm struggling to find a simple example of how to add another GUID partition to unallocated space on an existing GPT disk.

That's because it's no different from adding a partition on an existing MBR disk.

You keep using the term "GUID partition" as if it was some special kind. It's not. To create a new partition on a GPT-partitioned disk, you just create a partition using whatever partitioning tool you find most convenient. (Assuming, of course, a modern tool with GPT support.)

The only differences are positive – you don't need to make the "primary vs logical" decision because there's only one kind, and choosing the right partition type is a bit simpler even without prior knowledge because there aren't as many oddball special-case types as MBR had.

(Although a good partitioning tool should automatically offer the correct partition type ID for general usage, just like they already do so for MBR-partitioned disks...)

What is the right way to create an additional GUID partition, to fill the unused 610 GB? Preferably using the DiskPart command line utility.

In DiskPart, use create partition primary. (Although GPT does not have the primary/logical split, Windows uses the term to mean a generic partition on all disk types.)

In Disk Management (diskmgmt.msc), right-click the unallocated area, then select "New Simple Volume".

From a Linux system you can use gdisk (gptfdisk), or a recent version of fdisk from util-linux – in both, use the n command. It's still recommended to use Windows to format the partition as NTFS, though.

I'm also confused about what GUID partition "ID" is required to create a normal partition that I can format and mount as drive D:

The partition type is EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, also known as Microsoft Basic Data.

You do not need to enter it when using Windows' tools; it will be selected automatically when creating a "regular" partition ("primary" in diskpart, "simple volume" in diskmgmt).

When using Linux gdisk, the "short ID" is 0700, or you can paste the full GUID anyway.