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Initialize new disks

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If you add a brand new disk to your PC, and it doesn't show up in File Explorer, you might need to assign a drive letter for the disk. You might also need to initialize the disk before you use it.

You can only initialize a drive that's not yet formatted. When you initialize a disk, everything on the disk is erased. This action prepares the disk for use by Windows. After you initialize your disk, you can format it, and then store files on it.

Warning

If your disk already contains necessary files, don't initialize the disk. You'll lose all the files. Instead, we recommend troubleshooting the disk to see if you can read the files. For details, see A disk's status is Not Initialized or the disk is missing entirely.

Initialize a new disk

The following steps show how to initialize a new disk by using Disk Management. If you prefer to use PowerShell, run the Initialize-Disk cmdlet.

  1. Open Disk Management with administrator permissions.

    1. In the search box on the taskbar, enter Create and format hard disk partitions.
    2. Select and hold (or right-click) Create and format hard disk partitions, and then select Run as administrator > Yes.

    If you can't open Disk Management as an administrator, follow these steps:

    1. In the search box on the taskbar, enter Computer Management.
    2. Select and hold (or right-click) Computer Management, and then select Run as administrator > Yes.
    3. After Computer Management opens, go to Storage > Disk Management.

  2. In Disk Management, select and hold (or right-click) the disk you want to initialize, and then select Initialize Disk. If the disk is listed as Offline, first select and hold (or right-click) the disk, and then select Online.

    Some USB drives can't be initialized. These disks are only formatted and then assigned a drive letter.

    Screenshot that shows Disk Management for an unformatted disk with the Initialize Disk shortcut menu displayed.

  3. In the Initialize Disk dialog box, make sure the correct disk is selected, and then choose OK to accept the default partition style. If you need to change the partition style (GPT or MBR), see Compare partition styles - GPT and MBR.

    The disk status briefly changes to Initializing and then to the Online status. If initializing fails for some reason, see A disk's status is Not Initialized or the disk is missing entirely.

    Screenshot that shows the Initialize Disk dialog box with the GPT partition style selected.

  4. Select and hold (or right-click) the unallocated space on the drive, and then select New Simple Volume.

  5. Select Next. Specify the size of the volume, and then select Next again.

    For the volume size, the common approach is to accept the default size, which uses the whole drive.

  6. Specify the drive letter 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 Finish.

Compare partition styles - GPT and MBR

Disks can be divided into multiple chunks called partitions. Each partition, even if there's only one, has to have a partition style: GPT or MBR. Windows uses the partition style to understand how to access the data on the disk.

Most PCs use the GUID Partition Table (GPT) disk type for hard drives and SSDs. GPT is more robust and allows for volumes bigger than 2 TB. The older Master Boot Record (MBR) disk type is used by 32-bit PCs, older PCs, and removable drives such as memory cards.

You don't usually have to worry about partition style. Windows automatically uses the appropriate disk type.

To convert a disk from MBR to GPT or vice versa, you first have to delete all volumes from the disk, which erases everything on the disk. For more information, see Convert an MBR disk into a GPT disk, or Convert a GPT disk into an MBR disk.