Initialize SSD/HDD for Free and Fix 'Disk Unknown Not Initialized' Error

Tracy King updated on Sep 10, 2020 to Partition Manager | How-to Articles

"Hi there, do you know how to initialize a new SSD in PC? I recently bought a new SSD, and I added to my computer, but it won't allow me to create a new partition. It keeps asking me to initialize the disk with an error message " Disk Unknown is not initialized". How can I fix this issue?"

  1. 1. How to Initialize SSD/HDD in Windows 10/8/7 (3 Ways)
  2. 2. How to Initialize SSD/HDD on Mac

Why You Need to Initialize Hard Drive/SSD

Are you having a similar problem with your SSD or HDD that the disk drive is not responding or stay with an unallocated condition? Do you know why the system keeps asking you or forcing you to initialize HDD/SSD? Here below are the reasons and causes that you are in and why you have to initialize SSD or HDD:

  • New HDD or SSD does not show up in PC

When a brand new SSD or HDD is plugged into PC, it may not show up in This PC/Computer immediately. You have to initialize it so as to make it detectable and work for storing data.

  • Disk Unknown Not Initialized error

An error message such as " Disk 0 is unknown, not initialized, unallocated" may pop up if you try to open a solid-state disk or hard disk drive. This problem can occur to all Windows systems, including Windows 10/8/7, and the only way is to fix 'disk not initialized' error.

  • Logical Disk Manager cannot access a disk since it's not initialized

Sometimes, if a hard disk or SSD is not initialized into MBR or GPT, the system may warn you with an error message "You must initialize a disk before Logical Disk Manager can access it".

How to Initialize SSD/HDD in Windows 10/8/7 (3 Ways)

If you add a brand new disk to your PC and it doesn't show up in File Explorer, you might need to add a drive letter or initialize it before using it. There are three ways to initialize SSD or HDD in Windows 10/8/7.

If your disk already has files on it that you care about, don't initialize it - you'll lose all the files. You can export data with data recovery software. Then, initialize the disk by the following steps.

Solution 1. Initialize SSD/HDD with Free Software

You can initialize a disk easily and quickly with the help of EaseUS Partition Master Free. This free partition tool enables you to initialize a hard drive or an SSD with simple clicks. What's more, it is a superior free tool designed for everyone to manage partitions in Windows without data loss: beginners and experts alike. 


Follow the steps below to initialize HDD/SSD:

Download Now

 Windows 10 is supported

Step 1: Download the software

Download EaseUS Partition Master. Connect the hard drive or SSD to PC.

Step 2: Initialize your HDD/SSD

Right-click the target HDD or SSD and select "Initialize to MBR" or "Initialize to GPT" accordingly.

Fig 1. Initialize to MBR:

initialize to mbr

Fig 2. Initialize to GPT:

initialize to gpt

Step 3: Apply the operation

A pending operation of initializing disk to MBR or GPT disk will be added. Execute the operation and click "Apply".

click apply to start

Solution 2. Initialize SSD/HDD in Windows 10/8/7 with Disk Management

Here's how to initialize a new disk using Disk Management.

For Windows 10/8 users:

Step 1. Press "Win + R", type diskmgmt.msc. and click "OK" to open the Disk Management tool.

Step 2. Find the HDD or SSD that you need to initialize and right-click on it, and select "Initialize Disk".

initialize hdd or ssd with disk management

Step 3. In the Initialize Disk dialog box, select the correct disk to initialize. And then click "OK" to accept the default partition style, or you can change the partition style (GPT or MBR) as you want.

select the partition style

After this, reboot PC to keep all changes, and then your disk can be used properly.

For Windows 7 users:

Step 1. Right-click Computer and select "Manage" to open Disk Management.

Step 2. Right-click on the not initialized disk (HDD or SSD) and select "Initialize Disk".

Step 3. Select the disk(s) to initialize in the Initialize Disk dialog box and set the disk partition as MBR or GPT.

Reboot PC, and then your disk will be initialized to create new partitions on it for storing new data.

Solution 3. Run CMD to Initialize HDD or SSD

If you are familiar with Command Prompt, you can try this method. Again, back up data into another safe disk or external storage device if you have important data on it.

Step 1. Press Win+R and type: diskpart and hit "Enter".

Step 2. Type the following commands in Command Prompt and press Enter after each command.

Click to copy

If you want to initialize to MBR disk, in the command, input convert mbr instead of convert gpt, then, you've finished the disk initialize process with the above commands.

Also read: How to Fix Disk Unknown Not Initialized Error.

How to Initialize SSD/HDD on Mac

If you are a Mac user, you can also initialize your disk. This guide uses Mac OS X El Capitan or later. The procedure may be different from other OS versions.

Step 1. Connect your SSD to Mac with a USB adaptor. Select "Initialize" when you receive this message - The disk you inserted was not readable by this computer.

Step 2. Disk Utility will pop up if not, open Disk Utility and you shall see the SSD listed under External

Step 3. Select the SSD and then select "Erase" on top of disk utility

Step 4. Input your desired name of the partition, if you plan to install Mac OS onto the partition, choose OS X Extended(Journaled) as the format. Choose GUID Partition Map as Scheme. After you click "Erase".

The SSD should now be visible on your desktop with the new name you gave it, as well as during the drive selection menu if you run an OS X installer.

Additional Information About Partition Styles - GPT and MBR

When you initialize a disk, you have to choose your partition style - MBR or GPT. MBR and GPT are two accessible partitions styles on Windows-based computers. Disks can be divided up into multiple parts called partitions. Each partition has to have a partition style - GPT or MBR. Windows uses the partition style to understand how to access the data on the disk. You can know their differences in detail in this table. What's more, you can convert MBR to GPT or GPT to MBR according to your needs.

Comparison MBR (Master Boot Record) GPT (GUID Partition Table)
Supported Partition Numbers Maximum 4 partitions. Maximum 128 partitions.
Supported Disk Capacity 2TB (for 512B sector), 16TB (for 4Kn sector) No disk capacity limit 
Supported Boot Mode BIOS UEFI
Supported OS
  • Windows 10/8/7, Linux
  • Windows Server 2016/2012/2008
  • Windows XP/Vista (64bit for data only)
  • macOS and modern Mac OS X
  • Windows 7/Windows XP/Vista


Initialize SSD is one of the essential tasks. Knowing how you can initialize SSD on Windows and Mac can solve the uninitialized issue with ease. Initializing SSD and HDD in Windows 10, 8, and 7 is possible using free software, Disk Management, and DiskPart. It only takes a few steps to complete this process.

Download Now

 Windows 10 is supported

SSD Initialization Related Questions

Here are some related questions about SSD initialization. If you still have a problem, you can read on to get additional help.

How do I initialize my new SSD?

To initialize a new SSD:

Step 1. Download EaseUS Partition Master. Connect the hard drive or SSD to PC

Step 2. Right-click the target HDD or SSD and select "Initialize to MBR" or "Initialize to GPT".

Step 3. Execute the operation and click "Apply".

Do I need to initialize SSD?

When a brand new SSD or HDD is plugged into PC, it may not show up in This PC immediately. You have to initialize it so as to make it detectable and work for storing data.

How do I initialize my Samsung SSD?

To initialize Samsung SSD in Disk Management:

Step 1. Press Win + R, type diskmgmt.msc. and click OK to open the Disk Management tool.

Step 2. Find the HDD or SSD that you need to initialize and right-click on it and select Initialize Disk.

Step 3. Select the correct disk to initialize. And then click OK.

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Frequently Asked Questions

Why Choose EaseUS Partition Master?

"I've used Partition Master Professional many times to create, delete, format, move, rename, and resize partitions."PCWorld

"Partitioning tools have come a very long since the days of complicated command line utilities and EASEUS Partition Master is one of the most advanced programs available."TECH ADVISOR

"I love that the changes you make with EaseUS Partition Master Free aren't immediately applied to the disks. It makes it way easier to play out what will happen after you've made all the changes."Lifewire

Will the "Migrate OS" feature transfer the Windows system files only or the whole C drive?

To ensure that the migrated system will boot normally, the Migrate OS feature will transfer all the files in the system and the boot partitions. Generally, the boot partition is the C drive so the transfer will include all the files in C.

Does EaseUS Partition Master license apply to multiple computers?

The license of Partition Master Professional and Server editions can be used on 1 computer only, while that for for the Technician and Unlimited editions can be used on multiple machines.

What is the difference between EaseUS Partition Master Trial version and the Free version?

Free is for home users only, with most basic functions available such as partition resize and clone. While trial can help you understand how this product works and test what a full license can do on a business or server OS machine.

Will it cause any data loss after resizing the partition in EaseUS Partition Master?

Generally, it will not cause any data loss or boot issue by resizing a partition. However, in order to protect your data, we suggest that you backup the partition before resizing, in case of any unexpected situations such as power outages, computer hardware failures, etc. You can use EaseUS Todo Backup to backup the partition and its trial version is fully functioned for 30 days.

What should I prepare before resizing the partition?

On the partition that is going to be operated, there might be some files being occupied by other programs. To ensure a successful operation, we suggest that you close all the unnecessary software before resizing that partition. Otherwise, EaseUS Partition Master will detect the partition being locked by the other software and require a reboot to resize the partition under boot mode.

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How to Partititon a Hard Drive on Windows 10/8/7