Open Disk Management from command prompt
In Windows 10/8/7, there is a very useful built-in tool for managing disk and volume
related tasks. Some users may not know of this tool because it is buried deep down
in Windows. Luckily, you can open Disk Management from command prompt in all
versions of Windows and it is really quick.
Press Windows + R key to bring out the Run window. From there, type in “diskmgmt.msc”
and press Enter.

Then you will see Disk Management with all the disks and partitions listed. If you
right click on a partition or disk, it will bring out many available options. You
can shrink volume, extend
volume, delete volume, convert to GPT/MBR, convert to dynamic disk, etc.
Some of the options may be grayed out due to various reasons. For example, Disk
Management will not allow you to delete recovery partition, but you can delete recovery
partition from command prompt. For managing disk partitions, you can do more
with Windows built-in command utility DiskPart.exe.
Delete partition using disk management command
In case you may accidentally delete some crucial partitions, some partitions (for
example recovery partition) cannot be deleted in Disk Management. When you right
click on it in Disk Management, you will see the option Delete Volume is greyed
out.
Some computer manufacturer has made a factory recovery partition on the hard drive
that allows you to restore computer to factory default settings. It may also be
called OEM partition. Microsoft has mentioned that the factory recovery partition
will not be available after upgrading to Windows 10.
If you need to delete the OEM partition to free up a few gigabytes of space, then you
can use Diskpart commands.
1. Type “diskpart.exe” in the Run box and press Enter to
open DiskPart command window.
2. Type “list disk”
3. Type “select disk [disk number]”
4. Type “list partition”
5. Type “select partition [partition number]”
6. Type”delete”

When the operation complete successfully, you can exit DiskPart.
Extend partition or create new partition
If you delete a partition or shrink a partition, it will generate some unallocated
space. To make use of the unallocated space, you can either add it to the contiguous
partition or create a new partition.
To extend partition from command line, open Diskpart window and type the
following:
List disk
Select disk [disk number]
List partition
Select partition [partition number]
Extend size=n (if you do not specify the extend size, all unallocated space will be
added to the contiguous partition)

To create a new partition from command prompt, type the following:
List disk
Select disk [number]
create partition primary [size=n] or create partition logical [size=n]
assign letter=H (you can assign any unused drive letter to the new partition)
If your hard drive was initialized as MBR partition style, then it can only have 4
primary partitions or 3 primary partitions plus many logical partitions. Therefore,
if your hard drive already has 3 primary partitions and you need more partitions,
then you can create a logical partition.
Convert to GPT or MBR from command prompt
GPT partition style is more advanced than MBR. If you want to break the 2TB hard drive
limit, you can convert MBR to GPT. As you may know, GPT and MBR disks use
different boot mode. If you want to boot from MBR disk, you need to make sure BIOS
based Legacy mode is enabled. If you want to install Windows 10/8/7 on GPT disk, you
need to enable UEFI boot mode.
If you do not configure it right, Windows will fail to boot. If you receive the error
“Windows cannot be installed on this disk. The selected disk is of GPT partition
style”, then you need to either change
Legacy to UEFI or convert the disk to MBR disk.
To convert GPT/MBR during Windows installation:
1. Press Windows and F10 key simultaneously to open a
command prompt.
2. Type”diskpart”
3. Type”list disk”
4. Type “select disk [disk number]”
5. Type “clean”
6. Type “convert mbr”

This operation will clear all the data on the drive. If there is valuable data on it,
you should create a backup before applying this. If you want to convert MBR to GPT
disk, you just need to change the last command to “convert gpt”.
Convert FAT32 to NTFS files system from command prompt
Fat 32 is the most compatible file system, so most of the USB is formatted with FAT32
by default. When you try to move a file that is larger than 4 GB, you will receive
an error “the file is too large for the destination file system”. In that case, you
can convert FAT32 to NTFS without data loss.
You can type “cmd” in a Run box and press Enter to open a command line window.
In the command prompt window, type: convert [drive letter:] /fs:ntfs

After converting to NTFS, you cannot convert
back to NTFS unless you try third party tools.
Disk management software
If you need to more advanced features regarding disk and partition management, you
can use AOMEI Partition
Assistant. It is available both in GUI and command prompt. It provides more
features than Windows built-in disk management tools. For example, you can use it to
convert disk to MBR/GPT without data loss, convert dynamic to basic without
affecting OS.
It is very easy to use, just like Disk Management. You can just right-click on a
partition or disk and all the available operations will be listed. It provides 8
wizards to guide you every step of the way. It also allows you to preview the
partition layout before you actually apply any changes to your hard drive. You can
see the interface below:

As mentioned, it also allows you to partition hard drive
from command prompt.

As you probably know that Windows built-in disk management commands have some
limitations. For example, you can only extend volume when there is contiguous
unallocated space, and converting to GPT/MBR will wipe out all data on the disk.
Therefore, to perform advanced operations on disk partitions, you can use AOMEI
Partition Assistant.