Private Sub Workbook_BeforeClose(Cancel As Boolean)
Dim Msg As String
Dim Ans As Integer
Dim FName As String
Msg = "Would you like to make a backup of this file?"
Ans = MsgBox(Msg, vbYesNo)
If Ans = vbYes Then
FName = "F:\BACKUP\" & ThisWorkbook.Name
ThisWorkbook.SaveCopyAs FName
End If
End Sub