Check to see if you have the Server Manager from TechWorks (Technology Works) installed on this machine. The Server Manager does create a duplicate users and group file called SMBasis. This file is created in order to allow the remote administration to change users and groups from another machine. Server Manager makes a private copy of the Users and Groups Data file (SMBasis) when making changes, and then swaps the temporary file with the original Users and Groups datafile when the change is complete.
This problem should be referred to TechWorks/Santorini.