Registry: HKEY_USERS

The keys under the registry hive HKEY_USERS correspond to the user account SIDs of user accounts (starting with S-1-5-21-…) or a service[serivce) (starting with S-1-5-80-…)

The currently logged in user's hive HKEY_CURRENT_USER is a symbolic link to the respective key under HKEY_USERS.

Additionally, there is also a .DEFAULT subkey.