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27 December 2023  John Weaver  Senior Program Developer
 

Summary
Learn how to fix unallocated external hard drive without losing data and recover important data using the methods discussed in this article.



Table of contents

table iconI. The reason why the external hard disk becomes unallocated
table iconII. Use Renee Undeleter to restore the data in the unallocated external hard disk
table iconIII. Repair method of unallocated external hard disk
how to fix unallocated external hard drive without losing data

I. The reason why the external hard disk becomes unallocated

If you’re unable to view or access files on your external hard drive in the file explorer, Disk Management can provide insight into the partition’s status. If the partition is listed as “unallocated,” it could be due to the following reasons:
● A hard disk partition was accidentally deleted while cleaning a specific partition.
● Virus attack.
● File system error or device failure.
● The hard disk driver is outdated. Click here to view the steps to update the hard disk driver.
● used somediskpart command Repair the removable hard disk so that all partitions and volumes are cleared.
the reason why partition lost on SD card
If your external hard drive holds crucial information, it is advisable to utilize specialized data recovery software to scan and retrieve data from the device. Afterwards, you can address the issue of unallocated space on your hard drive. Below, we will introduce a program that can successfully recover data from an unallocated hard drive.

II. Use Renee Undeleter to restore the data in the unallocated external hard disk

1. What is Renee Undeleter?

Renee Undeleter is a software specially used to restore various data files. When you accidentally delete important files, empty the recycle bin, or format the disk/storage, you can use this tool to retrieve the lost data. The software covers four functional modules, including file recovery, format recovery, partition recovery and image creation, which can help you solve all data loss problems in an all-round way.
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Easy to use Recover data by 3 steps;

Multiple scan modes Fast partition scan, whole partition scan and whole disk scan;

Supported file types Image, video, audio, text, email and so on;

Image creation Create a partition image to read and back up data;

Supported devices SD card, SDHC, SDXC, USB flash drive, hard disk and computer.

Easy to use Recover data by 3 steps;

Multiple scan modes Fast partition/whole partition/whole disk scan;

Supported devices SD card/USB/hard disk.

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2. How to use Renee Undeleter to restore unallocated external hard disk data?

The steps are as follows:
Step 1: Connect the external hard disk to the computer, download and install Renee Undeleter on the computer, and then run it.

Select the (Whole Disk Scan) option on the main interface. This function can scan all the partition data that existed in the hard disk, even if the partition has “unallocated” space.

Note: Do not install on the disk that needs to restore data, so as not to cause data overwriting.
select whole partition scan in Renee Undeleter
Data recovery function introduction:
Fast Partition Scan – Quickly retrieve files lost due to accidental deletion or emptying the recycle bin.
Whole Partition Scan – Quickly recover files lost due to inaccessible or formatted partitions.
Whole Disk Scan – Analyze and get partition information and perform a full scan of the entire partition.
Image Creation – You can create a mirror image for a partition to back up the current partition state.
Step 2: Select the hard disk that needs to recover data, and click (Next).
select a disk to recover in renee undeleter
Step 3: Please wait patiently for the scan. This process will find all the partitions in the hard disk, and the “Select the partition you need to scan” window will pop up, then you can select a specific partition to scan. If not selected, all partitions will be scanned automatically, and more files can be found, but it will take longer.
Step 4: You can preview the files during the scanning process. If all the required files have been found, you can check the files to be restored, and then click the (Recover) button to restore the files to another disk.
select taget files to recover with renee undeleter

III. Repair method of unallocated external hard disk

1. Create a new simple volume for unallocated space

After successfully recovering the data from the unallocated space on the external hard drive, a simple volume can be created to utilize the space and access the partition normally. The process is outlined in the following steps:
Step 1: Right-click the (Start) menu, select (Disk Management), find the removable hard disk, right-click the unallocated space, and select (New Simple Volume).
create simple volume for SD card
Step 2: In the new simple volume wizard, set the simple volume size (that is, the partition size), and then click (Next).
set the volume size in new simple volume wizard
Step 3: Next, select the drive letter for the partition of the external hard disk, and click (Next).
assign a drive letter for the new volume
Step 4: Select the file system as NTFS, select the default value in “Allocation unit size”, and name the partition in “Volume Label”.

Then check the (Perform a quick format) option and click (Next).

Finally, click (Finish) and that’s it. If you don’t know which file system to choose, you can check: Features and differences of FAT32, exFAT and NTFS file systems.

format the volume with the settings
The method above outlines the process for recreating a partition in the unallocated space of an external hard disk. In the event that you accidentally delete the partition on your external hard disk and notice that it has become unallocated, this could be a sign of a faulty or damaged hard disk. In this case, you can perform a check and repair after rebuilding the partition.

2. Use the Windows system disk error checking function

Specific steps are as follows:
Step 1: Connect the external hard disk to the computer, press (Windows icon + R key), enter (diskmgmt.msc) in the pop-up box, and then click (OK).
run disk management
Step 2: In Disk Management, right-click the target external hard disk, and then select (Properties) on the menu.
partition of hard drive
Step 3: In the (Tools) column, click the (Check) button.
check disk
Step 4: If your system is Windows 7 or Windows 8, please check (Automatically repair file system errors) and (Scan and try to recover bad sectors), and Windows 10 automatically repairs all errors by default. Then wait for the inspection and repair to complete.

3. Use the chkdsk command to repair the external hard disk

Step 1: Search (cmd) directly in the search box in the lower left corner, and select (run as administrator) to open the command prompt.
run as administrator
Step 2: Enter ( chkdsk F: /f /r /x ) command and press the (Enter) key to check and fix external hard drive errors.
Chkdsk: Checks a volume’s file system and file system metadata for logical and physical errors.
F: Refers to the drive letter of the external hard disk;
/f will fix errors on disk;
/r will find bad sectors and restore readable information;
/x means to forcibly dismount the volume if necessary; any open handles to the drive will be invalidated.
Enter the chkdsk disk repair command