Retrospect uses VSS (Volume Shadow Copy Service) which is built into Windows to copy open files. On Windows, Retrospect uses the ROFF.sys filter driver.
Check the Retrospect License Manager (Configure>Licenses) to make sure you have the Open File Backup Add-On in your copy of Retrospect. If you don’t have the Open File Backup add-on, make sure you close all program prior to the backup.
Last Update: 14 February, 2012