HKEYS

HKEYS refers to the five principal root hives of the Windows Registry, a hierarchical database used by the Windows operating system to store configuration settings for the system, installed software, and user preferences. The registry is organized as a tree of keys and values, with HKEYs serving as the top-level roots from which all other keys branch.

The main hives are:

- HKEY_CLASSES_ROOT (HKCR): information about registered file associations and Class Registration, providing a merged view of HKLM\Software\Classes and HKCU\Software\Classes.

- HKEY_CURRENT_USER (HKCU): user-specific settings that apply to the currently logged-in user, including software preferences and environment settings.

- HKEY_LOCAL_MACHINE (HKLM): machine-wide configuration that affects all users, including hardware, software, and security policies.

- HKEY_USERS (HKU): contains data for all loaded user profiles, including per-user configurations and the default profile.

- HKEY_CURRENT_CONFIG (HKCC): hardware-related configuration profile representing the current hardware configuration.

Some contexts also reference HKEY_PERFORMANCE_DATA, which provides dynamic, read-only data used by performance monitoring tools rather than persistent configuration storage.

Access and editing of HKEYS typically occur through tools such as the Windows Registry Editor (regedit) or command-line utilities (reg.exe). Because the registry governs critical system and application behavior, modifications should be performed with care. It is common to back up keys or create a system restore point before making changes, and to use such edits only when guidance or documented procedures are available.