[3 Ways] Recovering Unallocated Space of A USB Flash Drive

Recovering unallocated space of a USB flash drive is super easy as long as you use the professional partition recovery software - AOMEI Partition Assistant. The deleted will be recovered as well.


By Lora / Updated on June 7, 2024

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Are you experiencing a situation where your USB flash drive stops working and shows unallocated in Disk Management? This also happens to a hard disk, USB drive, SD card, or pen drive. I can't imagine how frustrated you must feel. What's the hell?

Continue to read this article and learn more about unallocated space on a USB flash drive. This article also offers users several ways to fix unallocated space on USB drive easily.

Basic knowledge about unallocated space on a USB flash drive

 Before fixing or restoring unallocated space on a USB flash drive, you still need to know some basic knowledge about it. Let's get started now!

What is unallocated space on a USB drive?

"Unallocated" means this portion of the storage device has not yet been formatted and partitioned. It is not ready for storing data. You couldn't access the unallocated space, let alone add new data to it.

If you want to use the unallocated space on a USB flash drive, you can create a new partition to occupy the space or allocate it to an existing partition.

Why does my USB have unallocated space?

It's important to know how unallocated space on a USB flash drive is created, it gives us clues on how to recover it.  Below are some reasons for unallocated space frequently occurs:

  • Partition system change: When users try to burn the system to a USB drive, some operating systems, like Chrome OS and Linux, may change the partition system of a USB flash drive.  
  • Accidental deletion: Users may delete the partitions on the USB flash drive by mistake in Disk Management or with a partition manager tool.
  • Malicious virus attacks: Some viruses or malware could damage the partitions of USB flash drives.
  • Incorrect use of third-party software or incorrect formatting: These operations can also result in unallocated space on the USB drive or SD card.

How to recover unallocated space on a USB flash drive?

There are 3 efficient ways to recover unallocated space on a USB flash drive. If your disk is a brand-new one or there is no data, directly create a new partition or resize your partition with unallocated space. If you save any important data on this USB flash drive, it's suggested to recover files from USB flash drive first, or try professional partition recovery software to recover it.

Method 1. Create a new partition directly

If the USB is brand new or you don’t need to recover data from USB flash drive, you can directly create a new partition to use the allocated space. But if there are any important data, you will lose all of them. Because creating a new simple volume will overwrite them and make it unrecoverable. Kindly consider it carefully.

Part 1: Recover data from unallocated space  (Optional)

This step is essential for users whose important data is still in unallocated space. If you are one of them, it's wise to seek help from a powerful data recovery software - MyRecover.

It's embedded with advanced scanning methods, which can fully scan the unallocated space and find all the recoverable files with high speed and success rate. And keep their original file name, format, path, and quality after recovery.

  • Recover 200+ file formats, from documents to images, videos, compressed files, etc. So you can use it to recover PNG images, PDF files, Word documents, MOV videos, and more.

  • Locate files quickly: MyRecover supports filtering files of different types, date modified, and sizes, especially useful for recovering deleted files from specific folder.

  • Preview different file formats, such as  jpg, png,bmp, jpeg, tif, svg, gif, ico, etc.

  • Recover data from hard drive without OS: The Crashed PC Recovery feature in MyRecover is capable of creating bootable media and booting Windows PC when it fails.

  • Cost-free data recovery up to 500MB.

Step 1. Download and launch MyRecover on your computer. Hover the mouse over the unallocated drive and click Scan to scan.

Download Software Windows 11/10/8/7/Server
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Step 2. The software runs the scanning process from Quick Scan to Deep Scan automatically to find all the files in the unallocated space. During the process, you can search, filter, preview, and recover files from the unallocated space of a USB flash drive.

For example, to recover deleted PNG images, click Filter and select Type Image, then type .png in the search box to narrow down. You can also directly type its file name in the search box. Once found, double-click them to preview.


Step 3. Select the lost files or folders and click the Recover files button. You will be asked to select a location. Please select a new location instead of the original location to avoid data overwriting.


⚠️MyRecover has 3 editions: Free, Pro and Technician. The free edition supports recovering permanently deleted files in Windows 10 up to 500MB. Once exceeds, you need to upgrade to MyRecover Pro or Technician. The Technician edition is recommended for business users within one company.

Part 2: Create a new partition step by step

Step 1. Connect the USB flash drive to the computer.

Step 2. Press Win + R and input “diskmgmt.msc” to open Disk Management.

Step 3. Right-click the unallocated space and select “New Simple Volume”.


Step 4. Follow the new simple volume wizard (specify file system, size, etc.) to create a new partition.

Method 2. Resize unallocated USB drive partition

To use the unallocated space on a USB flash drive, you could resize the partition to allocate the space to the existing partition with partition manager - AOMEI Partition Assistant. If there are any important data, recover data from unallocated space using MyRecover, or skip to Method 3 directly.

Step 1. Launch AOMEI Partition Assistant after installing. Right-click the existing partition at the left of the unallocated space and select “Resize/MovePartition”.

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Step 2. Drag the slider to the end of the USB flash drive. The unallocated space would be added to the existing partition.

Move and Resize

Step 4. Click “Apply” to confirm the operation. Within a few seconds, AOMEI Partition Assistant will recover the unallocated space of a USB flash drive.

Resize Partition to Recover Unallocated Space

Method 3. Restore partition from unallocated USB drive

If your USB flash drive showing unallocated space suddenly, you could use a reliable partition recovery tool to recover both the files and partitions on the USB. The Partition Recovery wizard in AOMEI Partition Assitant will be a great choice for you.

With its Fast Search & Full Search methods, you can fully scan your USB drive for unallocated space and data files in it. It supports NTFS partition recovery, FAT32, Ext3/Ext4, and is compatible with Windows 7, 8, 10, 11, and Windows Server. 

  • Fast Search: Scan your USB hard disk quickly and locate lost partition on it. This is the recommended method. 

  • Full Search: Scan every sector of your flash drive to find lost partition and corresponding take longer. Try this method when Fast Search fails.

In addition, you can use it to recover deleted or lost partitions in HDD, SSD, USB drives, SD cards, and other storage devices.

Step 1. Select Recover > Partition Recovery at the top and click the disk containing the lost partition. Click on “Next” to proceed.

Parition Recovery Wizard

Step 2. Choose Fast Search for the first time as it takes less time. Then, click “Next”. 

Search Method

Step 3. The program lists all the lost or deleted partitions on the USB drive. Select the unallocated partition and click “Proceed”.

Select Lost Partition

The partition recovery will be completed in seconds. You could go to Disk Management to check the USB drive partitions.


Sometimes, you may find some of your files still missing from the lost partition, or you could not find the desired partition. In this case, try powerful data recovery software for Windows - MyRecover to get them back!


There are 3 effective methods for recovering unallocated space of a USB flash drive. You can choose the desired method depending on whether you need to recover your data or not. If there is any important data, please restore files from unallocated space using powerful data recovery software -MyRecover or directly recover unallocated partition & files with AOMEI Partition Assistant. 

To avoid the recurrence of unallocated space and consequent data loss, it is recommended to make a regular backup to keep copies of your files. One free but feature-rich Windows backup software - AOMEI Backupper is a great choice to help you, whether you want to create file backup, system backup, etc.

Lora · Editor
Lora is an editor of AOMEI Technology. She is also a tester and editor of AOMEI Data Recovery Tools. -- "Keep testing, write the most useful tutorials for helping people recover the lost data for Windows and phones" is the most meaningful thing for her. Dedicated to creating helpful tutorials, she hopes her tutorial can assist users to effortlessly solve data loss problems on their personal computers and mobile phones.