How to reformat a hard drive in Windows 11 and 10

Before you start

• Back up. Formatting removes access to everything on the volume. Copy what you need to another drive or cloud storage first.
• Check the drive letter and size. Most mistakes come from formatting the wrong drive. Unplug other external drives if you can.
• Reformatting isn’t secure erasure. A quick format leaves old data recoverable. If you’re selling or giving the drive away, follow how to secure wipe a hard drive or SSD instead.
• You need administrator rights to format a hard drive.

Choose a file system

File system	Use it for	Limits
NTFS	Internal drives and external drives used only with Windows	Macs can read NTFS but not write to it without extra software
exFAT	External drives shared between Windows and macOS, cameras and large files	No file permissions or journaling, so it’s less robust if unplugged mid-write
FAT32	Old devices that accept nothing else	4 GB maximum file size; Windows’ format tools only offer it for volumes up to 32 GB

Microsoft describes exFAT as the successor to FAT32, built for very large files and storage devices. Leave Allocation unit size at the default; Microsoft’s format documentation recommends the defaults for general use. For removable drives over 32 GB that must be FAT32, see how to format a USB drive to FAT32.

Reformat a drive in File Explorer

1. Open File Explorer and select This PC.
2. Right-click the drive and choose Format.
3. Pick the File system, type a Volume label if you want one, and leave Allocation unit size as it is.
4. Keep Quick Format ticked for a drive that works normally, or untick it to check the whole surface.
5. Click Start, then OK on the warning that all data will be erased.

Quick or full? A quick format deletes the file table and root folder without scanning for bad sectors. A full format takes much longer; Microsoft confirms that since Windows Vista it also writes zeros to the whole volume. Use full for an old hard drive you suspect has bad sectors. On an SSD a full format only adds wear, so quick is the right choice.

Reformat in Windows 11 Settings

Windows 11 has the same tool in Settings: go to Settings > System > Storage > Advanced storage settings > Disks & volumes, select the volume, click Properties and then Format. You choose a label and file system there too. Unallocated space on the same page offers Create volume.

Use Disk Management for new or old disks

Disk Management handles cases File Explorer can’t: a brand-new disk with no partitions, or a drive split into several volumes. Press Win + X and choose Disk Management, or run diskmgmt.msc.

• New disk: if Windows asks to initialize it, keep GPT. Microsoft says GPT is the default and suits most hard drives and SSDs; MBR is for older PCs and some removable media. Then right-click the Unallocated space, choose New Simple Volume, accept the full size, pick a drive letter and format it as NTFS.
• Existing volume: right-click it and choose Format. Microsoft warns that formatting destroys any data on the partition.
• Merge a drive back into one volume: right-click each volume and choose Delete Volume until the disk shows one block of unallocated space, then create a new simple volume.

Microsoft also notes that initializing a disk that’s already in use erases everything on it, so only initialize disks you’re sure are empty or backed up.

Reformat the whole disk with diskpart

An old system drive moved into another PC often has EFI and recovery partitions that Disk Management won’t delete. diskpart clears them all at once. Warning: clean removes every partition on the selected disk; check the disk number twice.

Open an elevated Command Prompt and run these one at a time, replacing 2 with your disk number from list disk:

diskpart
list disk
select disk 2
clean
convert gpt
create partition primary
format fs=ntfs quick label="Data"
assign
exit

clean removes the partition layout, convert gpt sets the partition style, create partition primary uses all the free space when you don’t give a size, and assign gives the new volume a drive letter. To delete only one protected partition instead, Microsoft documents delete partition override, which removes partitions diskpart would normally refuse to touch. It still can’t delete the system or boot partition of the running Windows.

Why you can’t reformat drive C:

Windows won’t format the volume it’s running from. File Explorer shows a message that you can’t format the volume because it contains the version of Windows you’re using, and in Disk Management the option is unavailable. To start over on the system drive:

• Reset this PC: go to Settings > System > Recovery, click Reset PC and choose Remove everything. This reinstalls Windows on a clean drive.
• Clean install: boot from a Windows installation USB and delete the old partitions during setup. See how to reinstall Windows 10 for both routes.

“You need to format the disk” prompt

If Windows says “You need to format the disk in drive X: before you can use it” when you plug in a drive that held files, click Cancel if you still need the data. The message usually means Windows can’t read the file system, and formatting would make recovery harder. Check the drive in Disk Management first: a missing or clashing drive letter can cause the prompt, and fixing the letter is enough. If the file system shows as RAW, recover the files with a data recovery tool before you format. For memory cards with the same problem, see how to format an SD card.

Related guides

• How to secure wipe a hard drive or SSD in Windows 11 and 10
• How to format a USB drive to FAT32 in Windows 11 and 10
• How to format an SD card in Windows 11 and 10 (4 ways)
• How to reinstall Windows 10: reset, repair install or clean install

Official sources:

• Microsoft Learn: Initialize new disks
• Microsoft Learn: format command
• Microsoft Learn: diskpart delete partition