Why my External Drive System Turned Unallocated?

Unallocated drives are drive volumes and partitions with undefined or damaged file system and unassigned drive letter that cannot be recognized and accessed by an operating system. In most cases, the issue is critical, which implies that your drive or volume is damaged and can lead to permanent data loss.

The most common reasons for a drive turning unallocated are related to file System error, outdated drivers, virus, or malware infection. A sudden power failure or surge can also damage a storage drive and lead to the unallocated drive volume issue.

As Windows cannot recognize an unallocated portion on a hard drive or external storage media, you need to allocate the drive partition by defining the file system and assigning a drive letter to it. This is done by formatting the affected drive or drive partition.

Apparently, formatting does repair the unallocated drive but the data contained in the drive is also permanently lost. Therefore, before formatting an allocated drive, ensure that you have taken the required backup to restore the data later.

Or else, you would need to use an advanced Windows data recovery software such as Stellar Data Recovery to get back the data from such unallocated drive partitions. The process is sometimes referred to as unallocated drive recovery where the external or internal drive has become inaccessible.

Steps to Recover Data from Unallocated Drive

1. Press ‘Windows+X’ and click ‘Disk Management’
2. Plug in the affected drive (skip this step if it is an internal drive partition)
3. Now note down the size of the unallocated drive partition.
   For instance, our drive has approx. an unallocated partition size of 4.46GB. (Refer to the screenshot)

1. Download and install Stellar Data Recovery-Standard

1. Run the data recovery software
2. Select ‘All Data’ from the available options, and click ‘Next’
3. Choose ‘Can’t Find Drive’ and click ‘Scan’
4. Under ‘Select Drive’, choose the storage media that contains the unallocated partition
5. Click ‘Search’ and the found partitions are listed under ‘Partitions Found’ checklist box
6. Choose the unallocated partition that has the same size as you see in the ‘Disk Management’ tool

1. Click ‘Scan’
2. If the desired data is not found during the quick scan, click on ‘Click Here’ link beside Deep Scan text at the bottom of the software window
3. Let the software finish the scan process
4. After the scan, the results are displayed in the left ‘Tree View’ pane
5. Click the ‘File List’ tab and choose the files and folders you want to recover
6. You can click on a file to preview it before recovery
7. After selecting files and folders, click ‘Recover’
8. Click ‘Browse’ and choose a location where you want to save the recovered data. Don’t select location on same drive or location for uninterrupted data recovery
9. Finally, click the ‘Start Saving’ button and wait for the software to save recovered files from the scanned unallocated drive

Now you can format the unallocated drive partition and access it normally. Transfer the recovered data to its original location after format.

At this stage, you have successfully performed unallocated drive recovery with the help of Stellar Data Recovery- Standard for Windows.

There are a few other alternative ways that you may try to repair and access an unallocated drive safely. However, use the following troubleshoot methods cautiously and at your own risk, as the process involved may cause further damage to your already inaccessible data or drive.

1. Use CHKDSK

Open command prompt in admin mode and type chkdsk /r /f X: and press Enter

The CHKDSK utility scans the drive for file system errors that might’ve turned the drive into an unallocated partition, and tries to fix those along with the bad sectors.

However, while fixing the bad sectors, the CHKDSK removes any data contained in the sector. This could cause data loss, so be careful, and keep a backup before running CHKDSK scans.

1. Disk Management

Disk Management lets you define the volume as RAW without formatting where you can then perform the data recovery process using tools like Stellar Data recovery. Later, you can format the drive and use it normally.

Also Read: How to Fix Unallocated SSD and Recover Data?

Conclusion

We discussed what an unallocated partition is, why a storage media might turn unallocated and how to repair it. Disk formatting is a sure shot method to assign a file system to an unallocated partition and thereby get it up and running.

However, formatting an unallocated partition also destroys access to the data present in it. Therefore, it’s recommended to have the data backed up before formatting the partition.

Or else, use a software to recover data from unallocated drive volumes and partitions.