Sub Workbook_Open()
Dim sh
For Each sh In ThisWorkbook.Sheets: sh.Visible = True: Next sh
End Sub
Sub Workbook_BeforeClose(Cancel As Boolean)
Dim n&, indx&, i&
n = ThisWorkbook.Sheets.Count: indx = ThisWorkbook.Sheets("Toto").Index
For i = 1 To indx - 1: ThisWorkbook.Sheets(i).Visible = False: Next
For i = indx + 1 To n: ThisWorkbook.Sheets(i).Visible = False: Next
End Sub