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.RBF File Extension

File Type 1	Retrospect Backup File (Most common)
File Format	File
Common?	No
File Description	Backup set containing data backed up with Retrospect backup software; contains actual files and folders backed up by Retrospect; can be restored based on the information saved in the .RBC backup catalog file. Retrospect was previously developed by Dantz software; the program is now owned and distributed by EMC Insignia.
Program(s) that open rbf files	Mac / Windows: EMC Insignia Retrospect or Retrospect Express

File Type 2	Windows Installer Rollback File
File Format	Proprietary File
Common?	No
File Description	Archive of files created during a software installation process run by Windows Installer; contains files that can be restored if the installation does not successfully complete; if the installation is successful, the rollback file is automatically deleted. The RBF file is saved along with a corresponding .RBS script file and stored in an archive named "Config.Msi."
Program(s) that open rbf files	Windows: Microsoft Windows Installer

Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/rbf