[Solved] Disk Unknown Not Initialized in Windows 10 or 11

If you are experiencing the disk "disk unknown not initialized" error on Windows 11,10, 8,7, please continue to read this article and get 6 effective solutions below.


By Ivy / Updated on April 2, 2024

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The "disk unknown not initialized" error is a common disk issue in Windows 11, 10, 8, and 7 and it usually happens to an external hard drive. It will show as "unallocated space" or no disk space in Disk Management.

It is frustrating as it will prevent users from accessing their disk and data on it. Don’t worry about this much. This article will introduce you to the possible reasons and several methods to resolve this error completely.

Possible Causes of Disk Unknown Not Initialized

The "disk unknown not initialized" error like disk 0 unknown not initialized, disk 1 unknown not initialized, etc can occur due to different reasons, such as outdated or damaged driver, virus attack, bad sectors, partition loss, file system error, MBR corruption, etc.

Unknown Not Initialized Unallocated

As you can see above, this error may be a little different, as the unknown not initialized disk sometimes shows no size. The most likely cause in this case is MBR damage. MBR, standing for Master Boot Record, is the first sector on an MBR or GPT disk that contains essential information about loading Windows and managing disk partitions.

Unknown Not Initialized No Size

How to Fix Disk Unknown Not Initialized in Windows 10 or 11

To fix the disk 0 unknown not initialized or disk 1 unknown not initialized error, the simplest method is to directly initialize disk in Disk Management. Although initializing a disk itself does not erase data, further operations such as partitioning and formatting will lead to data loss. Thus, if there are any data on it, you’d better recover data from uninitialized disk first.

Recover Data from Uninitialized Disk to Prevent Any Loss

Recovering data from not initialized disk is the most important things if you are sure there are important data on the disk. MyRecover is one of the most powerful data recovery software in Windows 11, 10, 8, 7, etc and able to recover data from health/problematic/damaged disk. It can be internal or external disk, USB drive, SD card, etc.

  • Scan the selected disk quickly and deeply with two advanced scanning methods and find out all the deleted or lost data completely.
  • Recover Word documents, Excel spreadsheets, PowerPoint presentations, photos, audios, videos, emails, webpages, and compressed files and 200+ file types.
  • Keep the recovered files with their original path, filename, format and quality.
  • Has a high success rate and fast speed, whether it’s deleted, formatted, virus infected, etc.

Step 1: Install and launch powerful data recovery software - MyRecover on your Windows PC. Hover the mouse over the unknown uninitialized disk and click Scan.

Download Software Windows 11/10/8/7/Server
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Select Partition To Scan

Step 2: It will run two advanced scanning methods - Quick Scan & Deep Scan automatically and display all the found files on the selected disk. You can filter and preview files in the disk. Here are two methods:

  • Click Filter and select a file type, such as Documents. Then, type file name or file extension in the Search for files or folders box.
  • Expand the Deleted Files, Recycle Bin, or Other Missing Files tab and check the deleted or lost files on the unknown uninitialized disk.

Scan Lost Data

Step 3: Select all the deleted or lost files on the unknown uninitialized disk and click the Recover x files button. You will then be asked to select a location. Please select a new location instead of the original location.

Select Deleted Excel Files Click Recover


  • The restore button will display the number of selected files and their full size. You can use it to determine the integrity of the recovered files.
  • Saving the recovered files to original location may cause data corruption or further data loss.
  • You can recover data from not initialized disk for free, up to 500MB in total. To recover all files on it, try advanced editions.
  • Except for recovering data from uninitialized disk, you can also recover data from RAW disk, recover files from a formatted hard drive, recover files from SSD, etc.

After recovering data from not initialized disk, please feel free to initialize disk or repair it without worrying about data loss. Here are 6 methods to help you.

Solution 1: Check Disk Connection

Initializing a disk will delete all the data on it. To be safe, you can choose to check the disk connection first. It may also cause the disk unknown not initialized error, show as not initialized, or display no information about disk capacity. 

  • Connect your external hard drive to a different USB.
  • Use the original cable to connect the hard drive.
  • Use a different cable to connect the external hard disk.
  • Or connect the external hard drive to another machine.

Solution 2: Update Device Driver

Updating the device driver can often resolve this issue. Because outdated or corrupted disk drivers also lead to the "disk unknown not initialized" error.  

1. Right-click on "This PC" (Windows 10 or 11) and select "Properties". Then, click on "Device Manager" on the right panel.

2. Expand the "Disk drives" section, locate & right-click the problematic disk, and choose "Update driver".


3. Select "Search automatically for drivers" and wait for the driver to be updated. Once completed, restart your system and check if the external drive appears.


Solution 3: Perform a Partition Recovery

If you suspect the cause of the unknown not initialized disk in Windows 11, 10, 8, 7, etc is partition loss, try partition recovery software like AOMEI Partition Assistant.

Step 1. Download, install and launch AOMEI Backupper Professional. Click “Partition Recovery Wizard” on the left panel and select the unknown not initialized disk. Click “Next”.

Try Demo Version Win 11/10/8.1/8/7/XP
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Step 2. Select Fast Search (Recommended) or Full Search. It’s suggested to try Fast Search and then Full Search (if you cannot find the lost partition). Click on “Next”.


Step 3. It will scan the problematic disk and display all the lost partitions. Select the desired partition and click “Proceed” to recover the lost partition from it.


Solution 4: Initialize the Disk

If the above methods are not working, you can directly try to initialize disk with MBR or GPT in Disk Management. This method also applies to initializing a new hard drive.

1. Right-click on "This PC" and select "Manage" > “Disk Management”.

2. Locate the target hard drive, right-click on it, and choose "Initialize Disk."


3. In the dialog box, select the unknown not initialized disk and choose either MBR or GPT partition style. Click OK to start the initialization process.

Initialize MBR or GPT

Solution 5: Rebuild MBR

If your problem is “external hard drive unknown not initialized no disk space”, the most possible reason is corrupted MBR. Try to rebuild MBR in CMD.

Step 1. Type “cmd” in the search box and select “Run as administrator”.

Step 2. Type the following commands and press “Enter” after each line.

  • bootrec /fixmbr
  • bootrec /fixboot
  • bootrec /rebuildbcd​​​​​​

Rebuild MBR

Step 3. Once done, type “exit” and press “Enter” to close this window.

Solution 6: Send for Manual Repair

If the disk 0/1/2 unknown not initialized 0 bytes is not fixed, you’d better seek professional help for manual repair. Physical damage may result in severe issues and experts are usually able to offer specialized solutions.

About Disk Unknown Not Initialized I/O Error

Absolutely, initializing the disk is the simplest method to fix the disk unknown not initialized disk error. But you may not perform this process successfully and receive an error message while initializing the disk, saying “The request could not be performed because of an io device error”.

IO Device Error

This may be caused by improper eject, virus infection (making damages to the partition table, MBR, etc), bad sectors, and other unknown damages. How to fix this IO device error?

  • Try chkdsk /f command to repair damaged disk.
  • Use convert mbr in DiskPart
  • Rebuild MBR
  • Format disk and assign a new drive letter
  • ...

The Bottom Line

If you want to fix an unknown not initialized disk without losing data, you need to recover data from uninitialized disk with a professional data recovery software first. It will find out and recover all of your data on this disk quickly and successfully.

As the entire initialization process will cause data loss. So it’s suggested to try disk connection and other 5 solutions before initializing a disk in Windows 11, 10, 8, 7, etc. And finally, to prevent data loss on a disk, the best practice is to create a file backup on a regular basis. Free backup software - AOMEI Backupper Standard do you a big favor.

FAQs about Disk Not Initialized Error

Here are some frequently asked questions and answers related to the "disk not initialized" error. If you still have questions about it, try to read below.

1. How do I fix SSD unknown not initialized?

Similar to a hard drive, the simplest method is to initialize SSD disk. But the problem is this process will cause data loss. So please recover data from the uninitialized disk first.

2. How do I force a hard drive to initialize?

For a new hard drive, you can directly initialize disk in Disk Management with its on-screen guide. If it’s a disk containing data, please copy and paste it to a safe place and then delete all existing partitions first.

3. Should I initialize disk MBR or GPT?

If your disk is equal to or smaller than 2TB, select MBR in the Initialize Disk wizard. If it’s larger than 2TB, select GPT instead.

Ivy · Editor
Ivy is an editor of AOMEI Technology, she covers backup & restore,hard disk & partitions management and cloud files transfer and so on for AOMEI. She is an outgoing girl and enjoys helping people find solutions to their problems. She loves traveling, eating, reading and so on. She usually hangs out with friends at her leisure time.