Specifies Yes (default) to set as read-only all files in your working folder that are not checked out, and No to leave the files as they are currently. If you specify Yes for this variable, Visual SourceSafe sets the read-only flag when you get, add, check in, or undo checkout of a file.
You can set this variable in your Ss.ini file directly or in Visual SourceSafe Explorer. In Visual SourceSafe Explorer, use the SourceSafe Options dialog box, Local Files tab. Select the Use read-only flag for files that are not checked out check box to set this variable to Yes.