Why need to format unallocated disk?
Unallocated space is the free storage on your disk that has not been in use. It can be used by putting system to put files on but there is no application can write to it. It is a waste to leave unallocated space on your disk alone. Your disk is not allocated, that is to say, there is no partition and there is only unallocated space on your disk. At this point, to make full use of your disk, it is fairly necessary to format it with certain file system.
How to format unallocated disk using CMD?
Diskpart is Windows built-in disk partition management command line tool that can help you to create partition, format partition, delete partition and so on. You can use this tool to format unallocated disk easily and quickly. Here are detailed steps (Take formatting unallocated disk using CMD in Windows 10 as an example):
1. Press Windows + R at the same time to open Run box.
2. In the Run box, type diskpart in the Run box and hit Enter key to run Diskpart utility.
3. In the Diskpart window, type the following commands one by one and pressEnter after every command.
list disk – to list all disk in the current system
select disk m – m is the number of the unallocated disk that you need to format
create partition primary
format fs=fat32 – you can replace this command with format fs=ntfs or format fs=exfat based on your need
assign letter f – f can replaced by other letter if you want
Now, your unallocated disk has been formatted and you’ll able to see the partition on it in Windows File Explorer.
Unable to format unallocated disk space
According to aforementioned, we can realize how to format unallocated disk using CMD in detail. However, you are not allowed to create partition on unallocated space on SD card or USB flash drive when it has hold one or more partitions; if you do that using Diskpart utility, you’ll receive the error message that “No usable free extent could be found. It may be that there is…”.You are also unable to format unallocated disk space larger than 32GB as FAT32 file system; when you format partition over 32GB as FAT32 via Diskpart, you’ll be prompted by the message that the volume size is too big. In view of the above, it is recommended to turn to 3rd party partition software to format unallocated disk (space).
Comprehensive 3rd-party partition manager: AOMEI Partition Assistant
Here AOMEI Partition Assistant Standard will be my first choice, which is compatible with Windows 10/8/7, XP and Vista. This powerful and reliable partition manager allows you to format unallocated disk to FAT32, NTFS, exFAT, Ext2, Ext3 and Ext4, so that your disk can work with differentoperating systems and electronic devices. It supports you to format large partition like 64GB in size to FAT32 and create second partition on SD card or USB flash drive. Besides, with intuitive interface, it is easy to handle even for green hand in computer. Have a look at how it works (Take formatting unallocated disk to NTFS in Windows 10 as an example).
Step 1. Connect your disk to the working computer and ensure that it can be detected. Then, download freeware AOMEI Partition Assistant.
Step 2.Install and run AOMEI Partition Assistant. In the main interface, find out the unallocated disk that’ll be formatted, right click the unallocated space on it and choose “Create Partition”.
Step 3. In this small pop-up window, you can specify the size and location of the new partition; assign a drive letter to it; choose the file system of it. Here NTFS is selected. Then, click “OK” to continue.
Step 4.Here you’ll return to the main interface where you can preview your operation. Then,click“Apply”>“Proceed” to perform it.
For step 3, if the drive letter of the partition is set as “None”, you’ll not be able to see it in Windows File Explorer.
For step 3, if you need to create partition on SSD, it is advised to tick the box before “SSD Partition alignment" under Advanced tab.
It’s an easy task to figure out how to format unallocated disk space using CMD. However, it is more advisable to try this 3rd party partition manager – AOMEI Partition Assistant out of its powerful functions and simple operation. Apart from functions mentioned above, AOMEI Partition Assistant is able to delete partition, resize partition and wipe partition on your disk. And my favorite function of AOMEI Partition Assistant is Migrate OS to SSD function that helps me to upgrade my hard drive to SSD without the trouble of reinstalling operating system. And if you need to migrate OS from MBR disk to GPT disk, you can upgrade AOMEI Partition Assistant to Professional version.