Registry root

Each tree's root key is identified by a constant whose name starts with HKEY_:

• HKEY_CLASSES_ROOT
• HKEY_CURRENT_USER
• HKEY_LOCAL_MACHINE
• HKEY_USERS
• HKEY_PERFORMANCE_DATA
• HKEY_CURRENT_CONFIG
• HKEY_DYN_DATA

There is not a single root key above these tree's root keys.