Private Sub Workbook_Open()

    Dim  As String
    Dim ϸ As String
    Dim  As Workbook
    
     = ThisWorkbook.Path & "\"
    ϸ = " .xlsx"
    
    On Error Resume Next
    
        Set  = Workbooks(ϸ)

        If Err.Number <> 0 Then
            
            If MsgBox("[" & ϸ & "]  ?", vbYesNo) = vbYes Then
            
                Application.ScreenUpdating = False
                    Workbooks.Open Filename:= & ϸ
                Application.ScreenUpdating = True
                
                ThisWorkbook.Activate
            
            End If
            
        End If

End Sub