How to Recover Data From an Unallocated Hard Drive and Fix the Issue

If one of your partitions (or entire disk) suddenly shows up as unallocated space for whatever reason, you’ve come to the right place. This problem is often not as dire as it might seem at first glance. Our team has gathered a collection of battle-tested methods that can help you recover data from the unallocated partition and restore it back to normal. Just keep reading, you’ll see exactly what to do.

Unallocated Disk Recovery Navigation

There are several common scenarios that result in unallocated space. It may range from user errors like accidentally deleting a partition or uncontrollable factors such as sudden power outages.

How to Recover Data From an Unallocated Hard Drive

Users looking to perform unallocated disk recovery have three options available to them–recover data from the unallocated drive using a third-party data recovery program, check if Windows has a backup of your data, or contact a professional data recovery service.

Let’s take a look at all three options in more detail:

Option #1: Recover Files from an Unallocated Space Using Recovery Software

The easiest way for most users to recover their files from unallocated space on their disk is to use a data recovery program. However, don’t rush to Google and download the first recovery tool you come across. Our team has tested many such tools and compiled a curated list of the best data recovery apps that you can rely on for safe and effective results.

Here is how you perform unallocated drive recovery using Disk Drill:

1. Download Disk Drill and install the program.
2. Open Disk Drill, and select the unallocated partition. It will simply show up as “Unallocated” on Disk Drill’s home screen. Click on Search for lost data and Disk Drill will begin scanning the unallocated space.
3. As the scan runs, you’ll see recoverable files pop up in real time. But it’s a good idea to let the scan finish completely. When it’s done, click Review Found Items to check out all the files it discovered.
   👀

   If you want to recover all found files simply click the Recover all… button.

   

4. Select the files you want to recover using the checkbox next to each one. You can filter the files by file type, size, and more. Each file you select will show a thumbnail preview in the pane on the right. For a closer look, Disk Drill allows you to fully preview any file type that your Windows installation can open—either natively or with the help of third-party applications you have installed. Just hover your cursor over the file’s name to reveal the eye icon and click it to access the full preview.
5. Once you’re sure, click Recover.
6. Select a recovery destination for the files. Click on Next.
7. Disk Drill will recover the selected files.

Option #2: Check Your System for Existing Backup

If you’ve enabled the Windows backup feature, called File History (and it was active BEFORE the partition became unallocated), you can get back your files if they were backed up.

It’s quite easy to perform unallocated drive recovery using File History:

1. Connect the storage device you used to set up File History.
2. Type “file history” in Windows Search (Windows Key + S).
3. Select the Restore your files with File History option.
4. Here, cycle through the backup you want to restore. Select the files using the checkbox, then click on the green Recover button.
5. File History will restore the selected file to its original location.

It’s always a good habit to create regular backups, and Windows File History can automate this process for you.

By the way, don’t forget to check your cloud backups if you have them active. Windows 10/11 come with OneDrive preinstalled, and there’s a chance you activated it during your initial setup. Who knows—you might find your files safely stored there.

Option #3: Contact a Data Recovery Service

In our experience, most drives/partitions become unallocated due to logical issues—such as accidentally deleting a partition, or corruption caused by a sudden power outage. However, there are cases where physical problems with the drive itself are to blame.

When physical damage is involved, standard DIY solutions might not do the trick. In these situations, a professional data recovery service may be your best (and sometimes only) option.

Typically, this is how data recovery services function:

1. ☎️ You contact a data recovery service and explain your data recovery scenario.
2. 🚚 The drive needs to be shipped or dropped off at the data recovery center.
3. 💵 The company evaluates the drive and informs you how much data is recoverable, as well as the cost. The evaluation itself is free.
4. ✅ You can decide whether you want to move forward with the recovery process.

Many top providers offer “No Data – No Charge” policies and highlight impressive success rates on their websites. However, there’s no guaranteed way to verify those numbers. Instead, rely on real customer feedback—check reviews and ratings on Google, Yelp, and Trustpilot to get a clearer sense of the service’s real-world performance.

Recently, we published an in-depth analysis of the data recovery services market, exploring the feasibility of recovering data at affordable costs. We believe it’s a worthwhile read.

How to Fix an Unallocated Partition

After you’ve successfully recovered your data from the unallocated partition (or if you don’t care about any remaining files), the next step is to make the unallocated space usable again. We’ll cover 4 methods that involve using Windows Disk Management (for two methods), the Diskpart command-line utility, and the TestDisk repair tool:

Option #A: Create a New Partition

The easiest way to handle partitions on Windows is by using the built-in Disk Management tool. It only takes a couple of clicks to create a new partition from the unallocated space.

1. Press Windows Key + R to launch the Run application. Type diskmgmt.msc in the text box and hit Enter. This will open Disk Management.
2. In the Disk Management window, look for the Unallocated section, as shown in the image below.
3. Right-click on Unallocated and choose New Simple Volume.
4. Click Next on the New Simple Volume wizard welcome screen.
5. On the next screen, specify a size for the new partition and click Next.
6. Assign a drive letter to your drive using the drop-down menu, then click Next.
7. If required, modify the format options on the next screen. You can leave them as default and simply click the Next option.
8. Click on Finish. Disk Management will create the new partition.

Option #B: Add Space to an Existing Partition

If you’d rather not create a new partition, you can merge the unallocated space into an existing one to get back unallocated disk space. This is perfect if you simply want to increase the available storage of a drive you already use, without adding another drive letter.

1. Press Windows Key + R, type diskmgmt.msc into the Run dialog box, and press Enter.
2. Locate the partition you want to expand. Right-click on it and select Extend Volume… from the context menu.
3. The Extend Volume Wizard will appear. Click Next and then specify how much of the unallocated space you want to add to the existing partition. By default, it selects all available unallocated space.
4. Click Next and then Finish to complete the process. The partition should now be larger, incorporating the previously unallocated space.

Option #C: Use CMD (Diskpart)

For users who are comfortable with the command line, the Diskpart utility provides an alternative to Disk Management.

1. Type cmd in Windows Search (Windows Key + S), right-click on Command Prompt > Run as Administrator.
2. In the Command Prompt console, type diskpart and press Enter.
3. After this, type list disk and hit Enter. The number under the Free column is the amount of unallocated space on your drive.
4. Type select disk x (replacing x with the disk number of the disk that has unallocated space–0 in our case) and press Enter.
5. Enter create partition primary size=x (replace x with the number listed under the Free column in the 3rd step). This is the size of the new partition that will be created. Press the Enter key.
6. Now, type list partition and press the Enter key.
7. On the next screen, type select partition x. Replace x the number of the newly created partition. Use the number listed under Size to find the partition easily, as it’ll be the same number you entered in step 5. Press Enter.
8. You now need to format the partition. To do so, type format fs=ntfs quick and press Enter. Wait for Diskpart to format the partition.
9. Lastly, you need to type assign and press Enter. If you have an older HDD, type active and press Enter after executing the assign command. If Diskpart displays an error after you type active, it simply means the command is not required.

Option #D: Use TestDisk

In cases where a partition has become unallocated due to corruption, lost partition tables, or other forms of logical damage, TestDisk might be the solution you need. It’s a free, open-source tool that we’ve successfully used many times before, and it excels in scenarios where you need to:

• Recover lost or deleted partitions.
• Rebuild damaged partition tables.
• Repair FAT, NTFS, and ext2/ext3 file systems.
• Fix boot sectors on FAT and NTFS volumes.

Much like Diskpart, TestDisk operates only through a command-line interface. But, before you can use it, you’ll first need to download the tool from its official website.

1. Head to the official TestDisk website. While version 7.3 is available, we recommend to download the stable 7.2 release for reliability.
2. Extract the downloaded files to a folder on your PC.
3. Open the folder containing the TestDisk files, right-click on testdisk_win.exe, and select “Run as administrator” When the program starts, choose [Create] to make a log file that records its actions and findings.
4. TestDisk will list all connected storage devices. Use the arrow keys to highlight the drive containing the unallocated partition, then press Enter.
5. TestDisk typically detects the partition table type on its own; press Enter to accept the suggested type, or select the correct one if you know it.
6. Highlight [Analyse] and press Enter to let TestDisk scan the selected drive for lost or deleted partitions. If initial results are incomplete, you can use [Quick Search] or [Deeper Search] for a more thorough examination. Once you locate the lost partition, highlight it and press Enter.
7. Choose [Write] to update the partition table, then press Y when asked to confirm your choice. This action will restore the previously unallocated partition.
8. After writing changes, select [Quit] to exit TestDisk, then reboot your computer. The once-unallocated partition should now appear as a normal, accessible drive in Windows Explorer or Disk Management.

FAQ