Hello Jo2710,

This where the Cancel argument comes in. Setting Cancel to True exits the event. Do this after the message is displayed.
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
If Environ("Username") <> "jrussell" Then
 MsgBox "You cannot save this form, click the Send button instead"
 Cancel = True
End If
End Sub