Solved - Recover Unallocated Partition on Windows 10

Key Takeaways:

• When partitions are accidentally deleted or lost, a healthy hard disk may appear as unallocated. You may need to perform partition recovery from unallocated space.
• AOMEI summarizes two ways to recover unallocated partitions on Windows 10: use CMD to recover unallocated disk or employ a professional partition recovery tool - AOMEI Partition Assistant.

Changes in operating systems, virus or spyware infections, or newly installed drives often result in unallocated disk space on the hard drive. This results in data being unviewable. The following is a typical case:

"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!" - from Microsoft Community

Don't worry, this article presents a comprehensive solution to recover unallocated partition with data on it.

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. Powerful unallocated partition recovery software

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.

The tool provides intelligent search and fully supports all Windows users. Free download this powerful partition recovery software and see how to fix an unallocated partition in Windows 10.

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.

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

Step 3. Choose one method according to your needs.

Step 4. Select the target partition and click Proceed.

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.

AOMEI Partition Assistant also provides more advanced features to help you better manage and improve the performance of your computer.

▶ Method 2. 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).

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

Don't miss method 1 if method 2 doesn't work.

What is 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. AOMEI Partition Assistant can help you recover unallocated space easily and safely.

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.