Solved - Recover Unallocated Partition on Windows 10

Do you want to recover unallocated partition on Windows 10? Here, we have rounded up 2 reliable methods to help retrieve lost partitions in Windows 11, 10, 8, and 7 computers.


By Dervish / Updated on March 26, 2024

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Help! How to recover unallocated partition



Help me! My E drive has 500GB and it is full of important files. However, I suddenly found out that it became an "unallocated" partition and I can't access it. I realized that my partition might be lost, but I don't know why this happened. Can someone tell me how I can get back my lost partition? Thanks in advance!"


What is unallocated space?

Unallocated Space

Unallocated space refers to the space on the disk that is not assigned any drive letter or does not belong to a partition. When installing Windows, you must partition the unallocated hard disk. Because Windows cannot be installed in a drive without a drive letter and file system.

In some cases, there will also be unallocated space on the disk that the user is currently using. These unallocated spaces do not belong to any partition and cannot write any data. If you want to use the unallocated space, you can create a new partition or add the unallocated space to another partition.

In rare cases, the hard drive can become unallocated. But sometimes, a healthy hard drive may appear unallocated, making all files and folders stored on it inaccessible. If you are in this situation, please read the following parts.

Why partition become unallocated space?

Some users may have questions: I didn't delete my partition, so why does the partition appear as unallocated? In fact, there are many reasons for a partition to be "unallocated". Here are the most reasons listed for you:

Power failure: If the computer loses power while writing to the drive, it can cause data corruption and delete partitions.
Attacked by a virus or malware: If a virus deletes a partition, the partition may appear as unallocated data.
Deleted partition by accident: A user caused the partition to be deleted by the wrong operation, thus showing unallocated space.
Bad sector accumulation: If a partition is damaged due to bad sectors, Windows may not recognize it.
The volume label, drive letter, or partition name is missing.

No matter what reason you want to recover unallocated partition on Windows 10, you can refer to this article. This post aims to show you how to recover lost partition on Windows 11, 10, 8, and 7 with detailed steps.

How to recover unallocated partition on Windows 10

There are 2 effective methods to recover unallocated partition on a Windows PC, including recovering unallocated partition on USB drives, external hard drives, etc.

▶ Method 1. How to recover unallocated partition using CMD

Sometimes a partition may appear unassigned because of a missing drive letter. So, you can reassign a drive letter to it. To do this, you can do it via CMD.

Step 1. Search for "CMD" in the start bar and right-click to "Run as Administrator".

Step 2. After entering "diskpart", type the following commands in sequence.

list volume and press Enter. After that, all partitions on your PC will be listed.
select volume 7 and press Enter (7 is the number of lost partition).
assign letter=F and press Enter (F is the drive letter you reassigned for this partition).

Assign Letter

Step 3. After saving and exiting, check whether the unallocated partition is recovered.

▶ Method 2. Powerful unallocated partition recovery software

Don't miss method 2 if method 1 doesn't work. AOMEI Partition Assistant Professional is one of the best partition recovery software on the market. Unlike CMD, this powerful tool provides a graphical user interface and users can recover unallocated partition on Windows 10 with a few clicks. More importantly, it provides two search methods: quick search and full search which can help users recover a full range of data.

Download Demo Win 11/10/8.1/8/7/XP
Secure Download

Warning: To ensure the successful recovery of the partition and data, please do not perform any other operations on this partition, otherwise the partition may not be restored.

Step 1. Install and run AOMEI Partition Assistant Professional. On the main interface, click Recover and select Partition Recovery.

Partition Recovery

Step 2. Then, select the disk where the unallocated partition is located and click Next.

Select Disk

Step 3. Choose one method according to your needs.

Choose Method

Step 4. Select the target partition and click Proceed.

Select Partition

Step 5. Click Finish to exit this window after you see the congratulations message.


Tip: Pro Version support to recover unallocated partition on Windows 11, 10, 8, 7, Vista, and XP. If you plan to recover partition on Windows Server 2022, 2019, 2016, 2012(R2), 2008(R2), and 2003, please switch to Server Version.

Bottom line

This is the whole process of recovering unallocated partition on Windows 10. In most cases, you can recover lost partition with AOMEI Partition Assistant Professional. But you should figure out the reasons why this happens to avoid it from happening again in the future.

Last but not least, there are more advanced features you can try like checking bad sectors, rebuilding MBR, data recovery, surface test, and more.

Dervish · Staff Editor
Dervish is an English editor of AOMEI Technology; He is delicated to offering users easy and effecitve solutions for issuses related to disks and partitoins. In his spare time, he enjoy wathcning films, playing footable, traveling and so on.