The Registry File Format

A registry (.reg) file is a text file that contains registry key paths, value names, and values. The key paths always begin with one of the five root key names: HKEY_CLASSES_ROOT, HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_USERS, or HKEY_CURRENT_CONFIG. The root key names designate the beginning location in the registry to update. For example, HKEY_LOCAL_MACHINESOFTWARExxx123abc specifies the xxx123abc subkey below the HKEY_LOCAL_MACHINESOFTWARE path. Below the key path in the registry file are value names and value pairs, collectively referred to as a registry entry. The registry can write any of the following data types for each registry entry: String, Binary, DWORD, Expandable String, or Multi-String. As Table A shows, in the registry file, the registry entries should consist of the following elements, with no spaces between those elements: