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

If you are experiencing the disk "disk unknown not initialized" error, don't worry about it, this article introduces you to 6 effective methods to fix it step by step without losing data.

By Ivy    Updated on May 8, 2026

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 and prevent users from accessing their disk and data on it. This is very frustrating.

Don’t worry about this much. This article will introduce you to the possible reasons and 6 proven methods to resolve this error easily and quickly.

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like disk 0 unknown not initialized, disk 1 unknown not initialized, etc can occur for different reasons, such as outdated or damaged driver, virus attack, bad sectors, partition loss, file system error, MBR corruption, etc.

As you can see above, this error may be slightly 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.

👍 Solutions to Disk 0/1 Unknown Not Initialized 

You can go directly to the corresponding method according to their reason.

Solutions Explanations
Initialize disk without data loss It's the simplest method to fix this error. But the further partitioning and formatting after initializing will cause data loss. So we suggest you recover data from a powerful software like FastRecovery. 100% safe.
Check disk connection If your disk suddenly becomes unknown, you can check if the cable is loose and try again.
Update device driver Outdated or damaged drivers may stop the communication between the operating system and your device.
Rebuild MBR The corrupted MBR may affect disk functionality. 
Partition recovery In addition, this error may be caused by partition loss. Please try clean and simple partition recovery software - AOMEI Partition Assistant.
Seek help from a professional If the above methods are not working, try to ask a professional for help, especially useful for the damaged disk.

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

Now, let's start to fix the disk unknown not initialized in Windows 10 or 11. Here are 6 ways in the following. 

Solution 1: Initialize Disk without Data Loss 🥇

Part 1. Recover Data from Uninitialized Disk 

FastRecovery is one of the most powerful data recovery software in Windows 11, 10, 8, 7, etc, and can recover data from healthy, damaged or formatted disks. It can be an internal or external disk, USB drive, SD card, etc.

❤❤❤ The unique advantages and shining points in FastRecovery
  • Scan the selected disk quickly or thoroughly for deleted or lost data.
  • Recover more than 1000 types of files, including images, documents (e.g., recover Word documents), videos, emails, audio, etc., without losing quality.
  • Locate files or folders on the not initialized disk quickly and accurately, and preview them before recovering.
  • Selective file recovery, not all, saving your precious time.
  • Compatible with Windows 11/10/8/7. Also, you can use it to restore deleted files from Windows Server 2016/2019/2022/2025 and previous servers.
Download SoftwareWin 11/10/8/7/Server
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⚠️Notes:
  • Don't download and install FastRecovery on the NOT initialized drive where you store deleted files, as this may cause data overwriting.

  • Any newly added data or disk formatting can overwrite data. Please avoid these operations after deletion.

Step 1. Install and launch powerful data recovery software - FastRecovery on your Windows PC. Click Deleted Files Recovery for fast recovery. You can also choose a more suitable alternative. All of them can help you retrieve data without causing any damage.

Step 2. Hover the mouse over the unknown uninitialized disk and click Scan.

Step 3. It will run Quick Scan automatically to find lost data. During scanning, you can click the Stop or Pause button if you select the wrong disk or something goes wrong. Scan time mainly depends on disk size and health, especially regarding bad sectors or file system corruption.

Step 4. Wait for the process to complete, then select files by Type (default) or Path, with options to sort, search, filter, and preview files

👉Under the Type section: 

  • Specify the data type and click the arrow next to type, size, date modified, etc., to sort files
  • To locate files quickly, type the file name or extension in the search box.
  • Or use the filter feature, similar to the Type category, allowing you to further specify the size of files, from less than 512 KB to 1GB above.
  • Once found, double-click the files to preview

👉 Under the Path section: Directly navigate to the original location where you saved deleted files. Sort files if needed.

⚠️Notes:
  • The Type categories and filter options include all supported data types, such as images, videos, documents, mails, web pages, compressed files, etc.
  • Click the Deep Scan to find more data if Quick Scan fails. It will scan every sector of the disk and take longer.

Step 5. Select deleted or lost files you want to recover and click Recover. Please select a new location to save the recovered data instead of the original location.

⚠️Notes:
  • Saving the recovered files to the original location may cause data overwriting.

  • 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.

Part 2. Initialize Disk 0/1 Unknown Not Initialized 

After recovering data from not initialized disk, feel free to initialize disk without worrying about data loss. 

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

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

Step 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.

Part 3. Format and Create a New Partition

After initializing the disk, it appears as unallocated space. You can create a new partition to save data.

Step 1.  Right-click "Start" and select "Disk Management".

Step 2. Locate the unallocated disk, right-click it, and select "New Simple Volume".

Step 2. In the New Simple Volume Wizard, specify the volume size, assign a drive letter, and whether perform a quick format. Remember to click "Next". 

Solution 2: 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 3: 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.  

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

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

Step 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 4: 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​​​​​​

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

Solution 5: 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 Partition Assistant. Click "Recover" and “Partition Recovery”. Then, select the unknown not initialized disk and click “Next”.

Free Download 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 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 can usually offer specialized solutions.

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 professional data recovery software first. It will find out and recover all of your data on this disk quickly and successfully.

FastRecovery

Professional data recovery software for unknown not initialized disk

As the entire initialization process will cause data loss. So it’s suggested to try disk connection and the 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 regularly. Free backup software - AOMEI Backupper Standard does 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. Will initialize disk erase data?
 
The initialize disk process does not delete any data, only formatting and creating a new partition and then storing data. So you might think that initializing disk deletes data.
2. 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.
3. 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.
4. When I try to initialize disk, incorrect function?
 
If you receive the error message "incorrect function" while initializing the disk, try to restart your computer and initialize the disk again. You can also try the following items:
● Check if the disk is online in Disk Management
● Make sure whether the cable is loose.
● Update disk driver
● Employ a professional data recovery software to retrieve data
● ...
5. When initializing disk, I/O 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. You can try the following methods:
● Try chkdsk /f command to repair damaged disk.
● Use convert mbr in DiskPart
● Rebuild MBR
● Format disk and assign a new drive letter
● ...
6. 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.
Ivy · Editor
Ivy loves teaching users how to recover lost data or backup files the easy way. With AOMEI FastRecovery and AOMEI Backupper, even beginners can do data backup, SSD cloning, data recovery files like a pro.