Fix Unallocated USB Drive

How to Fix Unallocated USB Drive & Recover Data

Last updated:

No robots used, our articles are crafted by humans under strict Editorial Guidelines.

Written by Joshua Solomon Joshua Solomon Contributing Writer • 53 articles Joshua Solomon, formerly a staff writer and now a contributing writer for Handy Recovery, has authored numerous articles on our site about data loss and recovery concerning Windows and external devices. LinkedIn Approved by Andrey Vasilyev Andrey Vasilyev Editor Andrey Vasilyev is an Editorial Advisor for Handy Recovery. Andrey is a software engineer expert with extensive expertise in data recovery, computer forensics, and data litigation. Andrey brings over 12 years of experience in software development, database administration, and hardware repair to the team. LinkedIn

Unallocated space on a USB is useless because you can’t store any data. Additionally, you can’t access this unallocated space, so data recovery becomes quite challenging.

Incorrect formatting, unexpected system failures and virus attacks are common culprits of USB unallocated space. This article explores techniques to fix an unallocated flash drive and recover data.

How to Recover Data from Unallocated USB Drive

Using third-party USB data recovery tools is your best bet for recovering data from an unallocated pen drive.

There’s a myriad of data recovery tools out there, and finding the right tool is analogous to hunting a needle in a haystack. Our expert team reviewed the best data recovery tools, and Disk Drill came out on top.

Disk Drill is an award-winning data recovery tool that offers powerful data scanning and retrieval capabilities. Additionally, the user interface is a breeze for new users looking to quickly recover deleted files from a flash drive.

The free version from Disk Drill permits data recovery of up to 500 MB. As a result, you can get started with data recovery for free. Compatibility isn’t an issue either as Disk Drill runs across various Windows versions: 7/10/11

This guide explores Disk Drill’s byte-to-byte backup feature to recover data from an unallocated USB stick:

  1. Download, install and launch Disk Drill.
  2. Select Drive Backup from the left panel. accessing drive backup in disk drill
  3. Now, select your removable disk and click Byte-to-Byte Backup. selecting drive for byte to byte backup
  4. Specify the destination to save the DMG backup file and click OK. selecting a destination for saving the disk image
  5. Now, click Done. disk image creation success alert
  6. In the data recovery menu, click Attach Disk Image. Select the disk image of your USB drive. attaching disk image into disk drill
  7. By default, Disk Drill chooses the All Recovery Methods scanning option. We recommend going ahead with the default setting to improve the odds of data recovery. Alternatively, you could experiment with the Quick Scan or Deep Scan. selecting disk image to scan
  8. Now select Search for Lost Data. Disk Drill will scan your USB drive to discover recoverable files. After the scan completes, click Review Found Items. reviewing found items on disk drill
  9. Disk Drill also depicts recovery chances for every file. You can also preview recoverable files by hovering over them and clicking the eye icon to reveal the last modified date and file path.

    Filters help narrow your search effectively—type in the desired file type. I wanted to retrieve some of my deleted Taylor Swift songs. So, I searched for “.mp3” and got some hits.

    previewing items on disk drill

  10. Now, select your files for recovery and hit Recover. selecting destination for data recovery
  11. Specify a destination for saving your recovered files and press OK. data recovery success alertNote: We recommend choosing a different location to save your recovered files to prevent mishaps like data overwriting.
  12. Click on Show recovered data in Explorer to navigate to your recovered files.

Note: Here are our 2 cents on any data recovery scenario: Always stop using the affected device or drive, as this decreases the likelihood of successful data recovery.

The bottom line is that Disk Drill is an end-to-end data recovery tool that is your one-stop solution for many data recovery scenarios. The tool facilitates data recovery from broken USB drives, formatted USB disks, and corrupted flash drives.


Disk Drill promises many more exciting features, including data protection tools like the Recovery Vault. Check out our complete walkthrough and documentation of Disk Drill’s various use cases.

How to Fix Unallocated USB Drive

Now, let’s address the elephant in the room. How exactly do you fix a USB unallocated problem?

We have covered three techniques to fix an unallocated USB drive:

Method #1: Fix Unallocated Space on USB Drive Using TestDisk

If you accidentally deleted a USB partition, the corresponding disk space would appear unallocated.

Here’s a quick guide on fixing your unallocated USB drive using TestDisk:

  1. Download TestDisk.
  2. Extract the zip folder. test disk zip extraction
  3. Launch TestDisk. launching test disk
  4. In the terminal window, select [CREATE] and hit Enter. creating log file on test disk
  5. Select the appropriate connected storage device and hit Enter. selecting the usb on test disk
  6. Now, you need to select a partition type table. Select Intel since you are on a Windows PC. selecting partition table on test disk
  7. Select the Analyze option and press Enter. triggering the analyze option on test disk
  8. Pick the Quick Search function and hit Enter. TestDisk will recover your deleted partition. recovered partition on test disk
  9. Select your partition and press P to reveal the partition files. Press Q to return to the partition list. After having selected your partition, press Enter.
  10. Select the [Write] option and hit Enter; Confirm by entering Y. entering the write partition command on test diskNote: If you didn’t get any hits, try conducting a Deeper Search.
  11. Reboot your computer to get back the lost USB partition – which essentially allows you to access the unallocated space. reboot alert on test disk

TestDisk has so much more to offer in addition to merely fixing unallocated disk space; Check out our complete dissection of TestDisk: Pros, Cons, and scan results.

Method #2: Recreate Unallocated Space Using Disk Management

Disk Management is a Windows native tool allowing users to perform storage tasks like drive initialization, shrinking a volume, and changing a drive letter.

Follow these steps to reclaim your unallocated USB disk space:

  1. Right-click on the Windows logo and select Disk Management. accessing disk management on windows
  2. Navigate to the unallocated volume; Right click > New Simple Volume. creating new volume on disk management
  3. On the installation wizard, click Next; Enter the new partition size, and hit Enter. installation wizard for new volume
  4. Select a drive letter to assign the new partition and click Next. drive letter assignment on disk management
  5. Configure the file system settings and click Next. file system configuration
  6. Click Finish.

Final Result

You can see that there is no unallocated space on the USB disk. Therefore, the entire disk space is now at your disposal.

result after disk space allocation

Now, the previously unallocated space should be accessible and ready to store data.

Method #3: Allocate the Space Using CMD (diskpart)

DiskPart is another native tool for converting the unallocated space on your USB into a new partition:

  1. Press Win and type in CMD; Select the Run as Administrator option. accessing cmd on windows
  2. Key in the following commands while pressing Enter after each line Diskpart List volume
  3. Find the volume containing unallocated space and enter this command: Select volume 3 Note: Use the relevant disk number while keying in this command). In this case, Volume 3 represents my pen drive.
  4. Now, execute this command: Create partition primary
  5. Finally, format the disk into an appropriate filesystem. For instance, if you want to stick with the FAT32 file system, use this command: Format fs=fat32 using cmd to format usb

Result: The above commands will help you restore the USB to its original state (similar to a factory reset default setting)

Note: Allocating space using CMD and recreating unallocated space using TestDisk yield the same results. We attempted to demonstrate two different techniques.


Here’s how you can fix an unallocated USB drive:

  1. Download, install & launch TestDisk.
  2. Select [CREATE] > Enter.
  3. Select the USB drive > Enter.
  4. Choose partition type table (INTEL for Windows).
  5. Pick [ANALYZE] > Enter.
  6. Choose Quick search> Enter.
  7. Select [Write] > Enter > Y.

Here’s how you can effortlessly restore unallocated space on your USB stick:

  1. Open Disk Management.
  2. Right-click the unallocated volume > New Simple Volume.
  3. Click Next > Enter.
  4. Select a drive letter > Next.
  5. Complete the configuration > Next.
  6. Click Finish.

Here are some common reasons behind a USB data loss:

  • Accidental partition table deletion
  • Virus attacks
  • Human errors like formatting the USB without backing up files
  • Incorrect USB ejection
  • Physical damage to the memory chip or USB connector

Here’s how you can recover data from an unallocated flash drive:

  1. Install & launch Disk Drill.
  2. Select your unallocated USB & click Byte-to-Byte Backup.
  3. Specify the destination > OK > Done.
  4. Click Attach Disk Image & select the image.
  5. Click Search for Lost Data > Review Found Items.
  6. Select files & press Recover.

Disk Management is your go-to tool for combining unallocated space on a USB:

  1. Open Disk Management.
  2. Navigate to the unallocated Volume; Right click > New Simple Volume.
  3. Click Next > Enter.
  4. Select a new drive letter > Next.
  5. Complete the configuration > Next.
  6. Click Finish.

Here’s how you can format an unallocated USB drive:

  1. Search CMD > Run as Administrator.
  2. Key in: Diskpart List volume
  3. Type: Select Volume 3 Replace ‘3’ with the relevant disk number.
  4. Key in: Create partition primary
  5. Enter: Format fs=fat32
  6. Wait for the process to format and restore your USB to original state.


Unallocated space on your USB drive can be frustrating, especially since you can’t save any data and access files in this “invisible” partition.

We’ve covered four techniques for you to fix your unallocated space problem and recover data:

Which of the above techniques did you try first? Leave a comment below.

About article
Contributing Writer Joshua Solomon

This article was written by Joshua Solomon, a Contributing Writer at Handy Recovery Advisor. It was also verified for technical accuracy by Andrey Vasilyev, our editorial advisor.

Curious about our content creation process? Take a look at our Editor Guidelines.

How do you rate the article? Submitted: