The system partition and the boot partition (also known as the system volume and the boot volume) are computing terms for disk partitions of a hard disk drive or solid-state drive that must exist and be properly configured for a computer to operate.
Since Windows NT 3.1 (the first version of Windows NT),[4] Microsoft has defined the terms as follows: Before Windows 7, the system and boot partitions were, by default, the same and were given the "C:" drive letter.
[7]: 971 Since Windows 7, however, Windows Setup creates, by default, a separate system partition that is not given an identifier and therefore is hidden.
This configuration is suitable for running BitLocker, which requires a separate unencrypted system partition for booting.
As of Windows 11, this nomenclature is still used by the "Disk Management" utility.