When your external hard drive becomes unallocated, relax! Follow solutions on this page to fix external hard drive unallocated errors without losing any data.

How to access unallocated external hard drive data

"Hey there, do you know how to fix an external hard drive with an unallocated error? My 1TB WD external hard drive suddenly shows up as unallocated in Disk Management on my PC. I don't want to format it for that I've saved quite a lot of important files on it. 

I cannot access saved data on the unallocated external hard drive, either. Help me please."

So how does your external hard drive become unallocated? Here is a list of reasons that may cause external hard drives or storage devices unallocated:

  • File system and internal device error 
  • Improper operations
  • Virus attack
  • Outdated disk driver

If you are experiencing the same issue on an external hard drive, USB drive, SD card or memory card, etc., stop using the device. In the following, you'll learn how to restore data, repair the unallocated external hard drive, and tips to avoid the unallocated issue.

Part 1. Restore data from unallocated external hard drive

Most users use an external hard drive to save valuable files and essential data. And when the external hard drive becomes unallocated, restoring data becomes the top priority. 

With the help of professional data recovery software such as EaseUS Data Recovery Wizard, you still have a chance to recover data from the drive. How? 

This software enables you to recover lost data from unallocated space on a hard drive or external hard drive with ease. Download EaseUS hard disk recovery software here and follow the guide below to restore data:

 Download for Win Recovery Rate 99.7%
 Download for Mac Trustpilot Rating 4.6

Step 1. Use a correct USB cable to connect your external hard drive to your computer. Run EaseUS Data Recovery Wizard and you will see your external disk under External drives. This software supports all the popular external disk brands, including WD, Seagate, Toshiba, LaCie, SanDisk, Samsung, etc. 

Select the external hard drive and then click the "Scan" button. 

select your seagate external hard drive and click scan

Step 2. As soon as the scan process starts, the software will find more and more lost and deleted data and display the data in the scan results. The recovered data will be nicely organized. You can quickly find the target files/folders by file type or search in the search box with exact file name. 

scan the lost data on the seagate external hard drive

Step 3. You can preview the files found by EaseUS Data Recovery Wizard's scanning algorithms. Then, select files and click "Recover". To avoid data overwriting, we recommend that you save the recovered data to a different drive than the original Seagate drive.

select files and click recover

Activation is required when you tend to restore all found files. Also, remember to save the recovered data to another secure device. 

 Download for Win Recovery Rate 99.7%
 Download for Mac Trustpilot Rating 4.6

Part 2. Repair unallocated external hard drive

It's easy to fix the external hard drive unallocated issue. All you need is to create a new partition on the external hard drive, set NTFS or FAT32 as its file system.

Here, you can try two free methods provided below for help. 

1. [Automated] Repair unallocated external hard drive with partition manager freeware 

By creating a new partition on the unallocated external hard drive with a compatible file system, users can store files on the device again.

Free partition manager software like EaseUS Partition Master Free supports to do so within 3 steps:

If you want to create a partition on an empty USB, SD card or external hard drive, connect it to your PC in advance.

Step 1. Launch EaseUS Partition Master. On the main window, right-click on the unallocated space on your hard drive or external storage device and select "Create".

Step 2. Adjust the partition size, file system (Choose the file system based on your need), label, etc. for the new partition and click "OK" to continue.

Step 3. Click on the "Execute 1 Task(s)" button and create a new partition by clicking "Apply".

Watch the following video tutorial and learn how to create a partition in NTFS, FAT, or EXT file system.

After this, you can save the previously restored data back to the external hard drive and even save more files on it again.

2. [Manual] Create a new partition on an external hard drive with Disk Management

Another free method that you can try is to create a partition on the unallocated device by using Disk Management. Be careful while following steps here to fix the unallocated external hard drive issue:

Step 1: Connect the unallocated external hard drive to the PC, enter Disk Management.

Right-click on This PC/My Computer > Manage > Disk Management.

Step 2: Locate and right-click on the unallocated space of the external hard drive, select "New Simple Volume".

Windows 10 disk management 2

Step 3: Set partition size, drive letter and file system (NTFS), etc.

Windows 10 disk management

Step 4: Click "Finish" to complete the process.

Windows 10 external hard drive partition

After this, you'll be able to use the external hard drive to save and store important data again. You can also transfer the previously restored data back into the external hard drive again.

Tips to prevent the external drives from becoming unallocated 

Here are some practical tips that you can follow to prevent further unallocated errors from happening on your external hard drive and other storage devices: 

  1. 1. Update external hard drive driver.
  2. 2. Recover NTFS partition on external hard drive with CHKDSK  or EaseUS partition manager software.
  3. 3. Run anti-virus software to clean up viruses in PC and external hard drive.
  4. 4. Use storage devices and unplug carefully from your PC.

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Updated by Tracy King

Tracy joined in EaseUS in 2013 and has been working with EaseUS content team for over 7 years. Being enthusiastic in computing and technology, she writes tech how-to articles and share technical solutions about Windows & Mac data recovery, file/system backup and recovery, partition management and iOS/Android data recovery.

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