.RBK File Extension

Backup file of the Windows 95 or 98 registry, which stores system and application settings, file associations, and other data; can be used to restore the registry if it becomes corrupted.

RBK files can be created using the Configuration Backup Tool (Cfgback.exe) included with Windows 95. Generally, the files are named Regback#.rbk, where "#" is a digit from 1 to 9.

Registry backups are also used by programs such as SQL Server 7.0 for saving SQL Server-specific registry entries. SQL Server 7.0 provides a program named Regrebld.exe which can be used for the backups.