4 Ways to Recover Unallocated Partition on PC (2025)

An unallocated partition can prevent data from being accidentally overwritten, giving you a chance to recover lost files. But it also makes that part of your drive inaccessible, and the files stored there cannot be opened or used. In some cases, if system boot files are located in the unallocated space, your computer may fail to start properly.

Don’t worry. Kingshiper Software provides 4 safe and effective ways to recover unallocated partitions on your PC. You can restore your data using Windows Disk Management, Command Prompt, or a partition recovery tool - AiRecover Data Recovery.

Part 1. Understanding Unallocated Space on a Hard Drive

“Unallocated space” is the part of your hard drive that hasn’t been assigned to any partition. The operating system sees it as free space, which can be used to create new partitions or extend existing ones.

Still, the thing is that this space isn’t really “empty.” In many cases, unallocated space appears because a partition was deleted or lost. That means the data that was stored there may still exist on the drive, but the system can’t find it anymore.

More Details about Unallocated Space

When a partition becomes unallocated, its data is usually not immediately erased. It simply becomes invisible to the OS and can be overwritten by new data.

• User mistakes: Accidentally deleting a partition or interrupting a resize operation.
• Software or system errors: Problems in Windows or partition tools can corrupt the partition table.
• Virus or malware attacks: Some malicious programs intentionally damage partitions, causing them to disappear.
• Hardware issues: Loose cables, bad sectors, or failing drives can make partitions unrecognizable to the system.
• System reinstall or upgrade mistakes: Deleting or misconfiguring partitions during Windows reinstall or upgrade can leave unallocated space.
• Connection problems: Loose or damaged SATA/USB cables can make the system temporarily misread a drive, showing unallocated space.

Part 2. Can I Recover an Unallocated Partition and Its Data?

“My hard drive suddenly shows a large block of unallocated space, and my previous partition, along with all its files, is gone. I’m worried about losing important photos and documents permanently, and I’m afraid that a wrong operation could make the drive completely unusable. Can I still safely recover my partition and data?”

It is a common concern for many users who suddenly encounter a lost partition or unallocated space. The good news is that in most cases, partitions that become unallocated due to logical errors can be recovered, and the underlying data often remains intact on the drive.

In this guide, we'll walk you through the entire process, including understanding the risks of unallocated partitions, taking precautions to prevent data overwriting, and using recovery software to restore lost partitions or retrieve your files, ensuring a safe and effective data recovery.

Part 3. How to Recover an Unallocated Partition on PC

Now that we’ve explored the possible causes and risks of data loss from an unallocated partition, let’s move on to the recovery process. From using disk management tools to scanning and restoring lost partitions with professional recovery software, this section will guide you through each step to get your data back safely. So let’s begin:

Way 1Recover Unallocated Partition with Partition Recovery Software

If your hard drive shows unallocated space, the most important thing is to recover your important files as quickly as possible. This is especially true if restoring the entire partition is difficult or not necessary. The easiest way is to recover the lost data directly.

Using partition recovery software to recover data from unallocated space is the safest and fastest option. Here are the main advantages:

• Deep scanning: Scans every sector of the disk and can recover files even if the partition table or file system is damaged.
• Works in many situations: Supports accidental deletion, formatting, partition corruption, virus attacks, and more.
• Easy to use: Intuitive interface, so beginners can handle it easily.
• File preview: Lets you preview files before recovery to make sure you’re getting the right ones.

Among many tools, AiRecover Data Recovery is highly recommended. It’s designed for data loss from unallocated partitions, with high recovery success, fast scanning, and a simple interface, making it great for both personal users and professionals.

How to recover files from unallocated space using AiRecover Data Recovery:

Step 1. Download and install the partition recovery software on a different disk to avoid overwriting lost data.

Step 2. Launch AiRecover and select “Deep Recovery” on the left. This mode can help you search the computer files thoroughly. Then, click on the “Recover” button.

Step 3. The software will show all disks on your computer. Select the disk with unallocated space and click “Scan” to do a deep scan to recover as much data as possible.

❗Tip: Scan time depends on disk size and the amount of data. Please be patient.

Step 4. After scanning, recoverable files will be shown by type or original location.

• Use filters to quickly find files by type, date, or size.
• Preview files to confirm they are what you want.
• Select the files or folders you want to recover.

Step 5. Click “Recover”, choose a different drive from the original disk as the save location, and start recovery.

Way 2Recover Unallocated Partition from File History

Using Windows’ File History to recover an unallocated partition can also solve this problem. For many users who had File History enabled before the partition became unallocated, this method works reliably. Here’s how to do it:

Step 1. Plug in the external drive that contains your File History backups.

Step 2. Go to Settings, and search for “Restore your files from File History”.

Step 4. Browse your backup and select the files or folders you want to recover. 

Step 5. Then click the green “Restore”, select “Restore to” to recover the files to a different location. Do not restore files directly to the unallocated partition.

Way 3Recover Unallocated Partition from OneDrive

Restoring files from OneDrive depends on whether users had enabled and configured OneDrive sync before the partition went missing. But this method is only applicable if the files were already backed up to OneDrive. If that’s the case, here’s what users should do to recover data from unallocated space.

Step 1. Go to the OneDrive website and log in to your account.

Step 2. Browse or search for the files and folders you want to recover.

Step 3. Select the files and click the “Download” button to save the files on your PC.

Way 4Recover Files from Unallocated Partition from Backup and Restore

Using Windows Backup and Restore is another common way to recover files from an unallocated partition. This requires users to have previously created backups using the Backup and Restore feature. Here’s how to recover data from unallocated space:

Step 1. Open “Control Panel” and go to “Backup and Restore (Windows 7)”.

Step 2. Click on the “Restore my files” button and find the files you lost.

Step 3. Click “Next” and select a location to restore your lost files.

Step 4. Lastly, press “Restore” to begin the recovery process.

Pat 4. How to Avoid Future Partition Problems

To avoid running into unallocated partitions or data loss again, follow these preventive measures to protect your disk structure, maintain partition stability, and keep your data safe.

Step	Why It's Important
Regularly check disk health	Monitoring S.M.A.R.T. status helps detect hardware issues early, preventing unexpected partition loss.
Maintain stable power and environment	Avoid sudden power cuts or physical shocks during disk operations to protect partition tables and file systems.
Safely eject external drives	Ensures all data is written and prevents file system corruption on removable disks.
Be cautious with disk management	Double-check before resizing, deleting, or formatting partitions to prevent accidental data loss.
Maintain the file system	Running disk check tools, such as chkdsk, to repair errors and keep partitions healthy.
Keep the system and drivers updated	Fixes known bugs and compatibility issues that could affect partition recognition.
Regularly back up important data	Ensures you can quickly restore files or partitions in case of unexpected issues.
Protect against malware	Using updated antivirus software prevents viruses from damaging partition tables, boot records, or disk structures.

FAQs on Recovering Unallocated Partitions on PC

Here are some FAQs on the topic to assist users further:

Q1: How do I fix an unallocated hard drive without losing data?

The safest way to fix an unallocated hard drive without losing data is to use professional data recovery software, like AiRecover Data Recovery. It can deeply scan the drive and recover your files to a safe location before creating a new partition.

Q2: Is it safe to format an unallocated partition?

Formatting an unallocated partition will permanently erase any data. It rebuilds the file system and creates a new partition, making old files almost impossible to recover. Only format if your data has already been recovered or is no longer needed.

Q3: How do I fix an unallocated partition in Windows 11/10?

Windows 11/10 users can restore unallocated partitions using Windows Disk Management:

1) Right-click This PC > Manage > Disk Management.

2) Right-click the unallocated space and select New Simple Volume.

3) Follow the wizard to set the partition size, drive letter, and file system.

This method creates a new partition. If you want to preserve existing data, recover it in advance before performing this operation.

Q4: What is the difference between “unallocated” and “free space”?

Unallocated space is storage not yet assigned to any partition, like empty land waiting for development.

• Free space is unused space within an existing partition, like empty floor space inside a room.
• You need to create a partition to use unallocated space, while free space can be used immediately to store files.