Use_Network_Name Initialization Variable
Specifies Yes (default) if Visual SourceSafe gets your login name from Windows network login information and automatically logs you in if it finds a match. The variable specifies No to always be asked for the VSS password. This initialization variable is used in the Srcsafe.ini file only.
The Visual SourceSafe Login dialog box is displayed unless you are supplying a user name in some other way, for example, through an environment variable.
You can set this variable in the Srcsafe.ini file directly or in Visual SourceSafe Administrator. In Visual SourceSafe Administrator, use the SourceSafe Options dialog box, General tab. Select the Use network name for automatic user log in check box to set this variable to Yes.