How to Reinitialize Hard Disk on Windows PC?

How can you reinitialize hard disk when disk shows unallocated in Disk Management? If you don’t know how to do it or meet problem during this process, you can follow this post to fix the issue.


By Lucas / Updated on May 12, 2023

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Why reinitialize hard disk?

When you have a new disk, no matter whether SSD or HDD after you connected well to your devices, you need to initialize it for further operations. Initialization is to select a partition style, MBR, or GPT, and then you can format to choose a file system, then you can store data on your disks.

Mostly, users will be asked to initialize the disk at first, however, there are some situations that may require users to reinitialize hard disk:

1. Choose an unsuitable partition style

Some users may not clearly understand MBR and GPT partition styles. After initializing their disks, they found the chosen type was not right for the later works. For example, some Windows OS doesn’t support GPT as the system disk, while some only use GPT disk as the system disk, like Windows 11. So, in this case, users need to reinitialize the hard disk.

2. Disk shows unallocated in Disk Management

In the second situation, disks seem unallocated in Disk Management. The unallocated error might occur on any storage device. Several circumstances can cause this problem, such as incorrect user operation, enlarging system partitions, crashing or shutting down the PC while dealing with partitions, converting file systems, etc.

Unallocated hard disk

3. Change disk settings

As the first point we’ve mentioned, Windows systems need different partition styles. If you didn’t initialize your disk to the right one, it would raise many problems in the future. Normally, an MBR disk only supports 4 primary partitions and you can only use 2TB space, even if your disk is larger than 2TB. Thus, if your disk is larger than 2TB, you need to initialize it to GPT type to maximize available space.

Of course, there must have many other requirements that ask users to reinitialize disk, next, we’ll show you how to do it.

How to reinitialize hard disk?

In this part, we’ll show 3 ways to reinitialize hard disk with Windows built-in tools and a third-party tool. Initializing a disk will cause data loss, so if you have the problem “does initializing a disk erase data”, now you know the answer.

Method 1. Using Disk Management to reinitialize hard disk

The most commonly used tool is Disk Management. The steps are also simple.

Step 1. In the search box on the taskbar, type Disk Management, right-click Disk Management, then select Run as administrator > Yes.

Step 2. In Disk Management, right-click the disk you want to initialize, and then click Initialize Disk. If this disk is listed as Offline, please right-click it and select Online at first.

Step 3. In the Initialize Disk dialog box, please check to make sure that the correct disk is selected, and then click OK to choose the partition style you want.

Initialize disk

Choose partition style

In this way, some people meet CRC issue. After they click initialize disk option, there’s a prompt that shows: Data error (cyclic redundancy check). According to Microsoft, a Data Error Cyclic Redundancy Check, or CRC error, indicates that the operating system has discovered a disk with faulty sectors or another intermittent problem on your storage devices.

Virtual disk manager crc error

This error may cause storage devices inaccessible, RAW, or not initialized. You can turn to the second method to try to directly initialize your disk again, or run CHKDSK to check your disk before initializing the disk again.

Method 2. Using Diskpart to reinitialize disk

If Disk Management can’t initialize your disk, then you can try Diskpart. Make sure you choose the right disk if there is one more disk on your PC, and ensure you type all commands correctly.

Step 1. You can press "WIN+R" and type "cmd" to open the prompt. Then, type diskpart in the prompt and press "Enter".

Step 2. Type the following commands and press "Enter" after each.

• list disk
• select disk x
• attributes cleared successfully (it can move to the next step smoothly)
• online disk
• convert mbr or convert gpt (to change the selected disk to MBR format or GPT format according to your requirements).

Initialize disk in Diskpart

Method 3. Employing third-party tool to reinitialize hard disk

Another option to reinitialize hard disk is using third-party tools. If you can’t handle commands in CMD, you can consider finding an alternative to do this job for you. Here we highly recommend an easy-to-use tool AOMEI Partition Assistant Standard. It’s a freeware that allows you to initialize the disk to MBR or GPT within 3 steps in Windows 11/10/8/7/XP/Vista.

And there are many other handy utilities you can employ to check your disk, such as “Surface Test”, “Check Partition”, etc.

Download FreewareWin 11/10/8.1/8/7/XP
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Step 1. Install and run AOMEI Partition Assistant Pro on Windows PC. Right-click the target disk and select “Initialize Disk”.

Initialize disk

Step 2. In this mini window, you can initialize the disk to MBR or GPT depending on your requirements. Choose a proper disk style and click “OK”.

Choose disk style

Step 3. Click “Apply” to commit the pending operation.


If your disk is fine and you only want to convert your data disk from MBR to GPT, you can choose the “Convert to GPT” function which won’t cause data loss.

For users who want to change the system disk partition style between MBR and GPT, or wish to convert data disk from GPT to MBR, we need to upgrade to the Professional Edition to employ this feature. The operation is also simple for all users.

Step 1. Launch the software, right-click the MBR disk you want to change, and choose Convert to GPT.

Convert disk to MBR/GPT

Step 2. In the pop-up windows, click OK to continue.


Step 3. Click Apply to operate and then your disk will be changed to GPT disk style.


Bonus tips: Recover lost data from reinitialized hard disk

If your disk shows unallocated after you reinitialized it, your data is lost. You can try the “Partition Recovery Wizard” function to restore.

Partition recovery wizard

Final words

To reinitialize hard disk, we list 3 ways for you according to different situations. If you are not surely about initializing disk MBR or GPT, you can check our links to learn more. AOMEI Partition Assistant is always your reliable disk and partition manager. There are many other helpful features such as cloning disk, OS migration, app/folder mover, and so on. In addition, it has the Server Edition for Windows Server users to efficiently manage devices.

Lucas · Staff Editor
I prefer peaceful and quiet life during vacation,but sometimes I watch football match if my favorite club performs brilliantly in that season. And I love reading, painting and calligraphy, thus I send my friends festival handwriting cards every year.