Hard drives and partitions

Learn methods of deploying Windows to different drives, including hard drives, solid-state drives (SSDs), or virtual hard drives (VHDs), and with different partition layouts, including with data and utility partitions.

Drive types

You can install Windows to a hard drive, such as a hard disk drive or a solid-state drive. For additional security, you can use hard drives that the factory has pre-encrypted. A single computer may contain multiple drives.

Solid-state drives

A solid-state drive (SSD) is a hard drive that uses solid-state memory to store persistent data. An SSD must have a minimum of 16 gigabytes (GB) of space to install Windows. For more information about drive space and RAM considerations, see Compact OS, single-sourcing, and image optimization.

Advanced format drives

You can use some Advanced Format Drives to provide additional drive space.

Advanced Format 512 emulation (512e) drives are supported on either BIOS-based or UEFI-based computers.

Advanced Format 4K Native (4Kn) drives are supported on UEFI-based computers only.

Factory-encrypted hard drives

To help protect your deployment environment, you can use a factory pre-encrypted hard drive to prevent unauthorized access before you install Windows or any other software. For more information, see Factory Encrypted Drives.

Multiple hard drives

If you install Windows on a device that has multiple hard drives, you can use the disk location path to make sure that your images are applied to the intended drives.

To do this, run diskpart and then SELECT DISK=<disk location path> to select each drive. For example: SELECT DISK=PCIROOT(0)#PCI(0100)#ATA(C00T00L00)

To learn more, see Configure multiple hard drives and Hard disk location path format.

Partitions

You can divide your hard drive into multiple partitions. You can create separate system, recovery, Windows, or data partitions.

To enhance the security of the Windows partition or a data partition, you can use BitLocker to encrypt the partition. For more information, see BitLocker Drive Encryption.

The partition types must match the firmware of the computer. You can install Windows on hard drives that are based on any of the following types of firmware:

• Basic Input/Output System (BIOS). Uses the Master Boot Record (MBR) partition structure.
• Extensible Firmware Interface (EFI) (Class 1): Uses the GUID Partition Table (GPT) partition structure.
• Unified Extensible Firmware Interface (UEFI) Class 2: Uses the GPT partition structure. Also includes a compatibility support module (CSM) that enables you to use BIOS functions, including the MBR partition structure. This module can be enabled or disabled in the firmware.
• Unified Extensible Firmware Interface (UEFI) Class 3: Uses the GPT partition structure.

To determine your system type, consult your hardware manufacturer.

System and utility partitions

A system partition is a partition that contains the hardware-specific files that are needed to load Windows.

By default, during Windows Setup, Windows stores these hardware-specific files in a separate partition. This enables the computer to use the following:

• Security tools. Some security tools, such as BitLocker, require a separate system partition.
• Recovery tools. Some recovery tools, such as Windows Recovery Environment (Windows RE), require a separate system partition.
• Multiple operating systems. If a computer has multiple operating systems, such as Windows 11 and Windows 10, the computer displays a list of operating systems. The user can then select which operating system to boot. When the system boot files are on a separate partition, it is easier to remove a Windows partition or replace the partition with a new copy of Windows.

Add system utility partitions before the Windows partition, because in the event that a full-system recovery is needed, this partition order helps to prevent the recovery tools from overwriting the system and utility partitions.

For information about how to configure system partitions while you apply images, see Capture and Apply Windows, System, and Recovery Partitions.

Microsoft reserved partition (MSR)

The MSR is used on UEFI/GPT systems, to support software components that formerly used hidden sectors.

• For more information about configuring MSR partitions, see Configure UEFI/GPT-Based Hard Drive Partitions.
• For more information about MSR partitions, see Windows and GPT FAQ

Recovery partitions

Add a separate partition for the Windows Recovery Environment (Windows RE) at the end of the hard drive, just after the Windows partition. With this partition order, if future updates require adding to or replacing the Windows RE tools partition, Windows will be able to manage the partition size automatically.

For BIOS/MBR-based systems, it's still possible to combine the Windows RE tools partition with the system partition. To save drive space, consider creating logical partitions to get around the four-partition limit. For more info, see Configure more than four partitions on a BIOS/MBR-based hard disk.

Data partitions

You can include a separate data partition to enable easier maintenance for situations where either the primary operating system is likely to be replaced, or when multiple operating systems exist on the same device, such as Windows 10 and Windows 7. When a device has multiple hard drives, a data partition may be stored on another drive.

See also