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'Disk Unknown Not Initialized' error: Why and How to Fix?

Updated on Friday, September 9, 2022

iBoysoft author Vain Rowe

Written by

Vain Rowe
Professional tech editor

Approved by

Jessica Shee

'Disk Unknown Not Initialized' error: Why and How to Fix?

Summary: The "disk unknown not initialized" error is often discovered as you plug an external hard drive into your PC, intending to copy data or files from it. This post presents you the reasons that cause the "disk unknown not initialized" error and methods to fix it. Finally, iBoysoft Data Recovery Software for Windows is highly recommended to fix RAW drive and recover lost data.

disk unknown not initialized on Windows

You may encounter this scenario: you insert an external hard disk, and a notification prompts you that the disk is successfully installed. However, there is no sign of the hard disk on This PC, and you cannot open and access the data on the disk at all. 

Then you may head to the Windows Disk Management utility, only to see that the external hard disk has shown a "disk unknown not initialized" error. Don't worry, this post is going to help you with detailed causes of this error. Meanwhile, professional approaches on how to fix the "disk unknown not initialized" error are also provided.

Table of Contents:


Why does 'disk unknown not initialized' occur on Windows?

Generally speaking, the reasons cause the "disk unknown not initialized" are multiple. You can have an eye over them:

  • Unstable power cable/USB port
  • Corrupt, incompatible, or outdated device driver
  • Corrupted file system
  • MBR corruption
  • Missing or lost partition table
  • Bad sectors

All these mentioned reasons are likely to lead to your disk's unallocated space. Take it easy, this error can be fixed with the help of the following professional methods.


Case 1: Disk unknown, not initialized, unallocated with space size

Open Disk Management, and locate the unallocated disk. If its status reads "Disk Unknown, Not initialized, Unallocated" with a certain space size, that indicates the hard disk is recognized by Windows operating system. 

Under this scenario, you can consider the following professional approaches to fix the "Disk Unknown, Not Initialized, Unallocated" error of the disk with a certain space capacity.

disk unknown not initialized with space size

Method 1: Check the power cable and USB port

An unstable power cable and USB port indeed lead to the "disk unknown not initialized" issue. Facing this, you can try a new cable or port to connect the computer and disks. If you can then copy data to the disk without a barrier, it's the mistake of the cable or port. Just throw the bad cable or port and try a new one. If you cannot, read further.

Method 2: Update the device driver manually

A device driver is a bridge that allows the PC to communicate with the external drive. However, when the device driver is corrupt, incompatible, or outdated for the external drive, then the communication fails. In such a case, updating the device driver is the priority.

  1. In the search box of the taskbar, type device manager, and then select Device Manager.           
    select Device Manager
  2. Select a category to see the names of devices, then right-click or double-click the device driver you'd like to update.
  3. Select Search automatically for updated driver software in relating dialog box.           
    select Search for automatically driver updated device manager on Windows
  4. Select Update driver.           
    select Update driver

If Windows doesn't have a new device driver, then you can try to look for one on the device manufacturer's website and follow their guides to update.

Method 3: Recover data and format the drive with a corrupt file system

Sometimes, the corrupted file system causes your disk to suffer the "disk unknown not initialized" error. Facing this condition, recovering the data on the hard disk is a must.

You're highly recommended to apply iBoysoft Data Recovery for Windows to recover your data, which thoroughly looks for recoverable files on a drive with a corrupt file system. for example, the RAW file system. Moreover, it even can find the lost partitions for data recovery.

  1. Download and install iBoysoft Data Recovery for Windows on your PC.
  2. Connect the uninitialized disk to your Windows computer as an external drive.
  3. Launch the recovery tool and select the Data Recovery module in the home window.  
    select Data Recovery in the home window
  4. Tick the Deep Scan option, click the Next button, then the scanning process will begin automatically.           
    scan data via iBoysoft Data Recovery software
  5. Right-click the found files to tap the Preview option from the RAW partition to see if the found files are intact.           
    preview the found files in iBoysoft Data Recovery software
  6. Tick all the data that you want and then click the Recover button.           
    sate the found files to another disk
  7. After the recovery process ends, please save the lost data to another disk.

The methods mentioned above are suitable if you want to recover RAW USB drive or SD card RAW recovery.

After you have recovered all the disk data, the steps to format the RAW drive are as easy as pie: 

  1. Right-click your hard drive, and then select the Format option.
  2. Choose a file system under the File System box.
  3. Tick the Quick Format option and then click the Start button to begin formatting.
    recover data and format the drive with a corrupt file system
  4. Click the OK button when the formatting work ends.

After you format the external hard drive, you can head to Disk Management to check if the "disk unknown not initialized" error is fixed.

Method 4: Rebuild MBR

MBR, or Master Boot Record, is the first sector of the hard disk. Every time you insert the hard disk into your PC, the Windows operating system tools read MBR on your disk first to know how it is partitioned.

If the disk experiences MBR corruption, the operating system cannot retrieve data on it absolutely. That's when the "disk 1 unknown initialized" hit. You can follow the steps below to rebuild MBR or fix MBR:

  1. Open a Command Prompt, and type the following command lines:bootrec/fixmbrbootrec/fixboot

Close the Command Prompt window, and check if the "disk 1 unknown initialized" error is solved. If not, keep reading.

Method 4: Initialize the disk

Initializing the disk indicates erasing everything on it, and then making it ready to use if it was not in service before. If the hard drive stores no important files and data, a way to initialize the disk is a good idea.

  1. Right-click My Computer and Select Manage, then locate and open Disk Management.
  2. Right-click the disk that shows the "disk unknown not initialized" error, and then click the Initialize Disk option. The USB drive has no option to be initialized, it just gets formatted and a drive letter.           
    select Initialize Disk on Windows
  3. Select between MBR partition style (Master Boot Record) and GPT partition style (GUID Partition Table), and then click the OK button. If you want to use this hard drive on various versions of Windows operating systems, you're recommended to select MBR, while the GPT disk is only supported on Windows 10 but isn't available for older OS versions.           
    select the disk has disk unknown not initialized error on Windows
  4. Select and right-click the unallocated space on the drive and then select New Simple Volume
  5. Select Next, specify the size of the volume (you'll likely want to follow with the default, which uses the whole drive), and then select Next.
  6. Specify the drive letter that you want to assign to the volume and then select Next.
  7. Specify the file system you want to use (usually NTFS), select Next, and then click Finish.           
    create a new partition and select a new file system on Windows

After the initialization process, go to This PC or Disk Management to check if the hard drive is fixed.

Initializing disk wipes out all data on the disk. If the hard drive contains lots of significant files and data, you'd better consider other ways to fix the disk unknown not initialized error. 

Method 5: Run the Diskpart utility

Many users point out that running the Diskpart utility really fixes some disk errors. However, running the Diskpart utility will format the disk partition and cause data loss. Hence, you need to back up first if you intend to take this approach.

Step 1: Press Win + R to open the Run window, and then type cmd to open Command Prompt.

Step 2: Type the following commands in the Command Prompt window, then hit Enter each time after you type them. 

This command will launch the Diskpart on the PC.


This command will list all the active disks on your computer.

list disk

Step 3: Type the following command, then hit Enter. This command selects the disk that disk space shows unallocated. You need to type the problematic disk's name.

select disk 0

Step 4: Type the command line and then hit Enter. This command line will create a new partition.

create partition primary

Step 5: Type the command line to assign a new letter for your drive, then hit Enter.

assign letter=H

Step 6: Type the command line below and hit Enter to go forward. This step will select the file system of your hard drive.

format fs=fat32 quick


fs=ntfs quick

Step 7: After the process ends, type the command line and hit Enter to close the Command Prompt window:


run Diskpart on Windows

Step 8: Restart the computer to see if the disk error is solved.


Case 2: Disk unknown not Initialized and no size in Disk Management

If Disk Management fails to grab any information about the hard drive or storage capacity, there are possibly disk errors or cartridge problems. Any operations may fail due to the "external hard drive not initialized I/O" error.

disk unknown not initialized without space size

Method 1: Power off the PC and remove the battery

The PC motherboard issue may cause the "disk unknown not initialized no size" problem. You can remove the battery to solve this problem:

  1. Turn off the computer, and then disconnect the drive from the PC.
  2. Remove the CMOS battery for ten more seconds.
  3. Insert the CMOS battery, and then turn on the computer.
  4. Shut down your computer.
  5. Connect the drive to your PC.
  6. Start the computer. 

If this method doesn't fix the disk unknown not initialized issue, keep reading!

Method 2: Replace the external hard drive

When the "disk unknown not initliazed" error happens in your disk, it's not surprising that Disk Management cannot show any information or size of the disk. At this moment, you'd better send this drive to professionals for help.

If the hard drive has any physical error, the only feasible way is to replace this ad drive with a new one.


Things you should know that how to use disk correctly

Disk errors are certainly annoying in daily life, and you can pay more attention to how to use disk correctly to avoid unexpected disk issues.

Firstly, ensuring that the disk is connected well is important, for a bad connection might cause a slow transfer problem. 

Secondly, visit the webpages and websites that are verified as safe sites by computer guards, because safe sites have no malware and virus to attack your PC or disk.

Thirdly, take good care of your disk, once the disk is physically damaged, you cannot fix it even if you rack your brain. Fourthly, bad sectors always hit suddenly and you need to back up files on disk timely to avoid data loss.

Last but not least, always back up the important files or data because disk errors happen unexpectedly, and if you find the disk doesn't work well, you'd better recover the data stored on it ASAP to avoid more data loss.


Indeed, disk errors like "disk 0 unknown not initialized" are really frustrating. Fixing the "disk 0 unknown initialized" error, patience is the trump card.

But don't be helpless, this article provides you with detailed reasons and ways to fix the "disk unknown not initialized" error, and you're able to try them to solve this tough issue.

Approaches to fixing disk errors are important, but knowing how to use a disk correctly is also essential. Read this post to know more about it.

 FAQ about the 'disk unknown not initialized' error


The "disk unknown not initialized" error always happens unexpectedly, and you can fix it by checking the power cable or the USB port, updating your device driver, rebuilding MBR, initializing the hard disk, and fixing the corrupt file system. Moreover, if this disk error is not fixed successfully, you're highly recommended to recover the data and then format the problematic hard disk.


You can initialize the unallocated disk by the following steps: Right-click My Computer > Select Manage > Locate and open the Disk Management > Right-click the problematic disk > Click the Initialize Disk option.