Unable to create new partitions on the unallocated space? Fix it now!

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Encountering error messages while installing Windows?
Reasons for failing to create a new partition on the selected unallocated space
Solutions for 'Failed to create a new partition on the selected unallocated space'

Seeing an error while installing Windows?

Here's a real-world scenario from answer.microsoft.com:

During the process of installing the Windows operating system (such as Windows 7/8/10/11) from a bootable device, your computer will prompt you to select a partition for the installation. If the disk you choose is labeled "Unallocated Space," you might encounter an error message when trying to create a new partition: "Unable to create a new partition on the selected unallocated space. [Error: 0x8007045d or 0x8004240f]."

Unable to create a new partition on the selected drive.

Is this error fixable? This article offers viable solutions and explains how to fix it using professional tools.

Reasons for "Unable to Create New Partition on Selected Unallocated Space"

If you receive an error message like "Unable to create a new partition on the selected unallocated space," "we could not create a new partition", the Disk Management tool is unable to create a new partition on the selected space. This can happen for several reasons, including too little space or too many partitions on the disk.

Another common installation error is:

Solution to "Can't Create New Partition on Selected Unallocated Space"

There are two ways to fix the “Can't create new partition on unallocated space” error. The first is by using the Command Prompt, and the second is by using a third-party partition manager. In this article, we'll explore both methods.

If you encounter difficulty using the command, you can refer to Method 2 to resolve the error "Can't create new partition on the selected unallocated space."

Solution 1: Clean and create new partition with Command Prompt
Solution 2: Merge partitions with partitioning tools

Solution 1: Clean and create new partition using Command Prompt

Note: Do not leave the Windows setup screen. Stay here and proceed with running Diskpart.

Step 1: While in the Windows Setup, press the Shift + F10 keys to open the Command Prompt window.

Step 2. Once the Command Prompt is open, type in the following command:

Type diskpart, and then press Enter.

Type select disk X (where X is the number of your target disk) and press Enter. You should see “Disk X is now the selected disk.”

Type clean all, and press Enter. (This might take some time, and then you'll see "DiskPart successfully cleaned the disk.")

Step 3: Create a partition.

Type create partition primary size=102400, and press Enter.

Type exit, and press Enter.

Solution 2: Merge partitions with Partition Master

AOMEI Partition Assistant Free is a safe and professional disk partition manager that can be used to merge, create, delete partitions, etc. With this partition management tool, you can resize partitions, extend partition, merge partitions, and split partition without data loss. In addition, this partition magic can also convert dynamic disk to basic disk and convert MBR to GPT when installing Windows 10/8/7 and Server 2016/2012/2008/2003 (32-bit and 64-bit). AOMEI Partition Assistant Home Edition is a free full-featured disk partition solution and free disk management software that helps you merge partitions without data loss.

Step 1: Choose the Destination Partition

Right-click on the partition that you want to merge and the one that you want to keep, and select “Merge.”

Run the partition manager software:

Step 2: Select the adjacent partitions to merge

Merge with the partition adjacent to the previously selected one.

Select the partitions to merge

Click “OK” to continue.

Step 3: Perform the merge partition operation

1. Click the "Perform Tasks" button at the top, then click "Apply." 2. The program will merge the partitions and add the contents of the second partition to the first.

People also want to know

How can I create a partition using unallocated space?

Create a partition from unallocated space:

1. Right-click the Windows logo and select Disk Management.

2. Select the disk you want to create partitions on.

3. Right-click the Unallocated space, and choose New Simple Volume.

4. Type the size of the partition, then click Next.

Can't create partition from unallocated space?

Can't create new partitions? It might be because you have too many external devices connected at once. Try disconnecting all external drives from your computer.

How to fix the new partition error during Windows 10 installation?

You can use DiskPart to create a new partition. If you receive an error when attempting to create the new partition, exit the Setup Wizard, and then choose Repair > Advanced Tools > Command Prompt.

Then type the command to create the partition.

Details...