How to Initialize an M.2 SSD in Windows 11

To initialize a new M.2 SSD in Windows 11, right-click the Start button and select Disk Management, right-click the new disk and select Initialize Disk, keep GUID Partition Table (GPT) selected, and select OK. Then right-click the disk’s unallocated space, select New Simple Volume, and follow the wizard so the drive gets a letter and a file system and shows up in File Explorer.

Applies to: Windows 11 (the same Disk Management steps are documented for Windows 10). Checked against Microsoft Support and Microsoft Learn on October 7, 2026.

Before you start

Initializing writes a new partition table to a disk. A partition table is the map that tells Windows where volumes begin and end. Microsoft warns that the initialization process erases all data on the disk, so these steps are meant for a new, empty SSD.

• Use an administrator account. Microsoft lists membership in the Administrators or Backup Operators group as a requirement for initializing a disk.
• Confirm the drive is empty. If an SSD that already held files suddenly shows as Not Initialized, do not initialize it. Jump to the troubleshooting section instead, because initializing or formatting it would work against getting those files back.
• Make sure the SSD matches the slot. M.2 is a physical shape, not a speed or a connection type. Kingston, an SSD manufacturer, explains that M.2 drives come in SATA and NVMe types that are not interchangeable, and that a SATA M.2 drive has two notches (a B key and an M key) while an NVMe M.2 drive has one (an M key). Check your PC or motherboard manual to see which type each M.2 slot accepts.
• Install the drive with the PC powered off. Follow the manual from your PC or motherboard maker for the screw, standoff and any heatsink, then start Windows from your existing drive.
• Know the capacity of the new drive. You will pick the disk from a list, and capacity is the easiest way to tell the new SSD apart from the drive that holds Windows.

An M.2 SSD in a USB enclosure can behave differently. Microsoft notes that some USB drives can’t be initialized and are only formatted and then given a drive letter.

Initialize the M.2 SSD in Disk Management

Disk Management is the built-in Windows tool for setting up disks and volumes. Initializing the disk and creating the first volume are two separate stages, and you need both before the drive appears in File Explorer.

1. Open Disk Management. Right-click the Start button, then select Disk Management. A window opens with a list of volumes at the top and a row for each physical disk (Disk 0, Disk 1 and so on) at the bottom. If Windows says you lack permission, open the Start menu, type Create and format hard disk partitions, right-click that result and select Run as administrator > Yes.
2. Find the new disk. Look in the lower pane for a disk marked Not Initialized, with its space shown as unallocated. Match the capacity to your new SSD. Do not go by the disk number alone, because the number depends on how the drives are connected.
3. Bring the disk online if needed. If the disk says Offline, right-click it and select Online.
4. Start the initialization. Right-click the disk itself, on its name at the left end of the row rather than on the unallocated space, and select Initialize Disk. The Initialize Disk dialog opens.
5. Check the disk and the partition style. Confirm the correct disk is selected. The default partition style is GUID Partition Table (GPT), which is the right choice for almost every Windows 11 PC. Select OK. The disk status briefly changes to Initializing and then to Online.
6. Create a volume. Right-click the Unallocated space on the disk, select New Simple Volume, and select Next.
7. Set the size. Accept the default size to use the whole drive as one volume, which is the common approach, and select Next.
8. Pick a drive letter. Choose the letter you want the SSD to have in File Explorer, and select Next.
9. Choose the file system. Keep NTFS, the usual file system for a Windows drive, and select Next.
10. Finish. Select Finish to prepare the new disk. After a few moments the volume shows a drive letter and a Healthy status, and the SSD appears in File Explorer.

There are other ways to reach the same tool. Microsoft also documents pressing Windows + R, typing diskmgmt.msc and selecting OK, and our guide to opening Disk Management in Windows 11 lists more.

GPT or MBR: which partition style to choose

The Initialize Disk dialog offers two partition styles. You normally do not have to change anything, because Windows preselects the appropriate one, but it helps to know what the choice means.

Partition style	What Microsoft says about it	Choose it when
GUID Partition Table (GPT)	Used by most computers for hard drives and SSDs. More robust, and allows volumes larger than 2 TB.	You have a modern PC with UEFI firmware, which includes every PC that meets the Windows 11 requirements.
Master Boot Record (MBR)	An older disk type used by 32-bit computers, older computers and removable drives such as memory cards.	The drive must also work in older hardware or an operating system that does not support UEFI.

The 2 TB figure matters for large SSDs. Microsoft explains that MBR can address only about 2.2 TB, so a disk bigger than that has to be initialized as GPT for Windows to use all of its space. Starting Windows from a GPT disk requires UEFI firmware rather than legacy BIOS, and UEFI is one of the published minimum system requirements for Windows 11.

Initialize the M.2 SSD with PowerShell

PowerShell does the same job with commands. Use this method only if you are comfortable identifying disks by number, because the commands act on whichever disk number you type. Open PowerShell as an administrator first.

1. List the disks. Type Get-Disk and press Enter. Windows lists every disk it can see. Find your new SSD by its size and note its number. A new, uninitialized disk has the RAW partition style.
2. Initialize the disk. Type Initialize-Disk -Number 1, replacing 1 with your disk’s number. With no other options, the command uses the GPT partition style.
3. Create a partition. Type New-Partition -DiskNumber 1 -UseMaximumSize -DriveLetter T, again using your disk number and a free letter of your choice. This creates the largest possible partition and assigns that letter. To let Windows pick the letter, use -AssignDriveLetter in place of -DriveLetter T; the two options cannot be combined.
4. Format the volume. Type Format-Volume -DriveLetter T -FileSystem NTFS. The default is a quick format, and the command returns a line describing the formatted volume.

Microsoft’s examples also show an MBR variant, Initialize-Disk -Number 1 -PartitionStyle MBR, for the rare case where you need the older style.

Confirm it worked, and how to undo it

Open File Explorer and look for the new drive under the letter you picked. Copy a small file to it and open the file again. In Disk Management, the disk should now read Online with a single Healthy volume that shows your drive letter and NTFS.

Initializing a disk does not copy Windows to it or make it bootable. Moving an existing Windows installation or doing a fresh install on the new SSD is a separate job. If you want several drive letters on the one SSD instead of a single volume, our guide to creating a partition on an SSD in Windows 11 covers sizing and splitting the space.

If you picked the wrong partition style on an empty drive, it can be changed, but only while the disk has no partitions or volumes on it. Microsoft’s DiskPart documentation states that a disk must be empty before it can be converted from MBR to GPT, so decide on the style before you copy files to the drive.

Troubleshooting

The SSD does not appear in Disk Management at all

Windows can only initialize a disk it can detect. Work through Microsoft’s general checks in this order:

• In Disk Management, select Action > Rescan Disks.
• Shut the PC down completely, then turn it back on.
• Right-click the Start button and select Device Manager. Look for a device with an exclamation point, select it and read its status. One approach Microsoft suggests is to right-click the problem device, select Uninstall device, and then select Action > Scan for hardware changes.
• Power the PC off and reseat the SSD, and confirm in your PC or motherboard manual that the slot supports your drive type (SATA or NVMe).
• Try the drive in a different PC. If it is not detected there either, the drive itself is the likely problem, and the SSD maker’s warranty support is the next stop.

Initialize Disk is missing or greyed out

The command appears when you right-click the disk’s label at the left of its row. If you right-click the unallocated space or a volume instead, you get a different menu. If the disk is Offline, right-click it and select Online first. If the disk already shows Online with unallocated space, it has been initialized, and you can go straight to New Simple Volume. If you are not signed in with an administrator account, reopen Disk Management with Run as administrator.

The disk is initialized but there is no drive in File Explorer

An initialized disk with only unallocated space has no volume yet. Right-click the unallocated space and select New Simple Volume. If the disk has a Healthy partition with a file system but no letter, right-click the volume, select Change Drive Letter and Paths, select Add, choose Assign the following drive letter, pick a letter, and select OK.

The volume shows RAW instead of NTFS

RAW means the partition has no file system. If you know the drive is empty, right-click the partition and select Format. Formatting erases everything on the volume, so do not use it on a drive whose files you are trying to recover.

A drive you were already using shows Not Initialized or Unknown

Microsoft says a disk listed as Not Initialized may never have been set up, but its formatting may also have become corrupted, or the disk may have a hardware problem. If the drive held files, stop before initializing it. Try the detection checks above, test the drive in another PC, and treat it as a reminder to check your backups.

Disk status is Unreadable

A disk can show Unreadable briefly while Disk Management is rescanning. If the status stays, Microsoft’s advice is to rescan the disks or restart the computer and see whether it changes. An Unreadable disk that never recovers may have failed.

You see EFI System or Recovery partitions

Those belong to the drive that runs Windows, not to your new SSD. Microsoft’s guidance is to leave them alone, because the PC needs them to start and to recover from problems. If you see them on the disk you were about to initialize, you have selected the wrong disk.

Work or school PC

On a managed computer you may not have an account in the Administrators group, and Disk Management will not let you make changes. Ask your IT department to set the drive up.

Frequently asked questions

Does initializing an M.2 SSD erase it?

Yes. Microsoft states that the initialization process erases all data on the disk. On a brand-new drive there is nothing to lose. On a drive that has been used, back up its files to another location first.

Is initializing the same as formatting?

No. Initializing sets the partition style (GPT or MBR) for the whole disk. Formatting puts a file system such as NTFS on a volume. A new SSD needs both, plus a drive letter, and the New Simple Volume wizard handles the formatting and the letter in one pass. Our article on formatting an M.2 SSD in Windows 11 looks at the formatting stage on its own.

Should I choose GPT or MBR for Windows 11?

GPT. It is the default in the Initialize Disk dialog, Microsoft describes it as more robust, and it is required to use all the space on a disk larger than about 2 TB. Choose MBR only if the drive also has to work with older hardware or software that does not support UEFI.

Can I initialize the disk without formatting it?

Yes. Initializing and creating a volume are separate, and the New Simple Volume wizard also has a Do not format this volume option. The drive will not be usable for files in File Explorer until a volume is created and formatted.

Should I use a quick format or a full format?

A quick format is enough for a new, empty drive, and it is what PowerShell’s Format-Volume command does unless you ask for a full one. Microsoft describes a full format as writing to every sector of the disk, which takes much longer. A quick format creates a new file table but does not fully overwrite the volume.

Do I need to initialize the SSD before installing Windows on it?

The steps in this article prepare a second drive for storage from inside Windows. Initializing does not make a disk bootable, and installing or moving Windows onto the SSD is a separate task with its own steps.

Do NVMe and SATA M.2 drives initialize differently?

No. Once Windows detects the drive, Disk Management lists it as a disk like any other and the steps are identical. The difference is in the hardware: the slot has to support the type of drive you bought.

Why does Disk Management ask for administrator permission?

Changing how a disk is laid out can destroy data, so Windows limits it to accounts in the Administrators or Backup Operators group.

With the SSD initialized and showing in File Explorer, the next step is to start using it: move large folders over, or point new app and game installs at the new drive letter. For reference, Microsoft’s own instructions are in Initialize new disks and Disk Management in Windows, with fixes for stubborn drives in Troubleshoot Disk Management.