External Hard Drive Lost Partition? How to Recover It Without Data Loss?

People often partition their external hard drive into several sectors to organize data for different purposes. Unfortunately, one of them may be lost or become inaccessible for some reason. If you are facing the same issue and have important files stuck in those partitions, you are in the right place. In most cases, you can recover a lost partition on the external hard drive without losing your data. How exactly should we do it? This guide introduces several methods we have verified. Let’s take a look at them.

Table of contents

Why Is A Partition on Your External Hard Drive Lost or Inaccessible?

Are the Files Still There After an External Hard Drive Partition Is Lost?

How to Recover the Lost Partition on an External Hard Drive Without Data Loss

How to Recover A Partition Shown As RAW on an External Hard Drive Without Formatting

Summary

FAQs

Why Is A Partition on Your External Hard Drive Lost or Inaccessible?

You may not have noticed problems with one of your partitions for a long time because you don't use external hard drives as often. In that case, it can be hard to pinpoint the exact cause(s). Therefore, we have listed these common issues for your reference to help you avoid similar problems in the future.

• 📑 Partition table corruption. Improper ejection of your external disk, sudden power failure, software errors, or virus infections can cause some information in the partition table to go missing, be erased, or be destroyed. This will prevent the operating system from being able to identify the starting and ending points of this partition, causing it to be regarded as "Unallocated" and not displayed in File Explorer.
• ⚙️ File system failure. Similarly, for one of the reasons above, the partition's file system may have become corrupted. Although it may look normal, you may get prompts like "Formatting is required before use" or "The drive cannot be accessed" when you try to access the files.
• 🔖 Partition letter is missing or removed. This is a case of "partition pseudo-loss", usually caused by remnants of the previous mapping in the registry, accidental deletion of drive letters, driver issues, connection failures, etc.
• ⛔ Incorrect operation. You might delete the partition in Disk Management, hide it, or accidentally interrupt formatting or repartitioning.
• ⚠️ Hardware failure: Your external hard drive has too many bad sectors, damaged read/write heads, and an aging control board, which causes the partition information to be unable to be read correctly.

Are the Files Still There After an External Hard Drive Partition Is Lost?

It should be your first concern, right? As mentioned earlier, no matter what caused the partition loss, it simply means the partition's information is missing or corrupted; the files within it are intact. Though you can’t see them on your screen, they’re still stored in their original locations. So, if you want to restore the lost partition on an external hard drive and the files within it successfully, please follow the suggestions below.

• 🚫 Do not rebuild or format the partition without guaranteeing the security of the data. This may destroy some of the original partition's information, making recovery more difficult.
• ✏️ Do not write any new data to this external hard drive to prevent previous files from being overwritten.
• 🛠️ Do not try to perform physical repairs yourself unless you have received professional training. Physical repair could cause permanent damage.

How to Recover the Lost Partition on an External Hard Drive Without Data Loss

Alright, now we are finally going to take actual action. Although you might lose an external hard drive partition for several reasons, each scenario has a corresponding solution. The following are proven methods. We suggest you check them one by one so you don't miss any viable options, and make sure your external disk is connected to the computer before you start.

Method 1. Reassign the Drive Letter

Just like our identity card, the drive letter is unique. If it is missing or duplicated, the operating system cannot locate the partition on the external hard drive, so that it won't appear in File Explorer. This may make you think it's been lost. Therefore, please follow the steps below to assign a new one.

1. Open "Disk Management". You can right-click on the "Start" icon on the taskbar and find it in the context menu.
2. It will list all connected storage devices. Find your external hard drive at the bottom of the window. It appears as "Removable."
3. As shown in the screenshot below, right-click on the partition you have lost (it appears with its original name but without a drive letter) and then select "Change Drive Letter and Path".
4. In the open window, click "Add" to assign a drive letter. Then click "OK." Your missing partition will reappear in File Explorer.

Method 2. Use DiskPart

Simply put, like the method above, this method also fixes the drive letter issue. The difference is that you do it through the command line.

1. Press the "Win" + "R" keys, then type "CMD" into the Run dialog box and click "Ok" to open the Command Prompt.
2. Type "diskpart" and press Enter. If you see the User Account dialog box, then click "Yes".
3. Finally, type the following commands one by one.

   list disk

   select disk (external hard drive number)

   list volume

   Select volume (your lost partition number)

   Assign letter=(unused drive number, such as M)

Method 3: Use A Professional Disk Tool

Once you have ruled out an incorrect drive letter as the cause of the missing partition on your external hard drive, the next solution is to use a tool to recover it without data loss. It will perform a sector-level scan, analyzing residual partition information such as boot records, file allocation tables, master file tables, etc., to recalculate the lost partition's starting position and full boundaries for restoration.

Here, we suggest trying iBeesoft Disk Partition Wizard. It’s very easy to use. It can help you clone the disk, convert file systems, resize your partitions, and more.

Here are the steps for how to recover the lost partition on your external hard drive

1. Download and install iBeesoft Disk Partition Wizard. Do not install it on the external hard drive with the lost partition.
2. Launch it and then click "Partition Rescue" in the sidebar.
3. In the disk list on the right side of the window, select the one with the lost partition, then click "New Scan."
4. Please wait patiently. iBeesoft Disk Partition Wizard will search for any available information. After the process completes, you should see all lost partitions listed. Please choose the one you need based on the capacity, then click "Recover". If it doesn't appear in the list, you can also click "Full Scan".

Method 4: Recover data from the lost external hard drive partition for free and rebuild the partition

Unlike the previous method, this method puts your files' safety first. As we mentioned in part 2, no matter how you lost the partition on the external hard drive, nothing happens to your files. Therefore, we will use iBeesoft Free Data Recovery as an example and guide you through the full process of recovering data and then rebuilding the lost partition.

1. Click the "Download" button to get the iBeesoft Free Data Recovery .exe file, then double-click it to complete the installation.
2. After launching it, hover your mouse over the area displaying the lost partition on your external disk and click the "Scan" button that appears to scan the data in the lost partition. As shown in this screenshot, it is usually named "Lost Partition - [Number]," and its icon has a yellow warning mark.
3. In the results window, you will see all the recoverable files and folders. Select the ones you need by clicking the checkboxes next to them.
4. Click the "Recover" button at the bottom right of the window. iBeesoft Free Data Recovery will let you select a location to save the data recovered from the lost partition on the external hard drive. Please do not save it to the original disk.
5. Just as in Method 1, open "Disk Management."
6. Finally, right-click the volume marked as "Unallocated," then choose "New Simple Volume," and follow the on-screen instructions to recreate it.

How to Recover A Partition Shown As RAW on an External Hard Drive Without Formatting

Does a partition on your external hard drive appear as "RAW" in Disk Management? When you try to open it, you receive a prompt saying, "It needs to be formatted before using"? When this happens, it means there is a problem with its file system, preventing the operating system from recognizing it. Although you can clicking "Format Disk" can fix this error, it will erase all data on it.

Fortunately, iBeesoft Disk Partition Wizard offers an alternative way without formatting. To do this, you simply need to select "Repair RAW Drive" under "Partition Rescue".

Summary

Lastly, we are confident that the methods introduced above will help you recover a lost partition on your external hard drive without data loss. However, prevention is better than cure. Therefore, please make sure to use your external hard drive correctly, such as,

• ⏏️ Always use the "Eject" option when removing it from your computer.
• 🔍 Check it periodically with tools like CrystalDiskInfo, making sure it is normal.
• ✅ Try to keep at least 20% of the storage capacity empty to preserve stable performance and lengthen its lifespan.
• 📤 Last, and most importantly, please back up your important files regularly.

FAQs