Set Calculation mode Manual to only one excel file

Hi,
You can do this by changing the workbook into a XLSM file and adding two event procedures in Visual Basic Editor (ALT+F11 to open):

Private Sub Workbook_Open()
Application.Calculation = xlCalculationManual
End Sub

Private Sub Workbook_BeforeClose(Cancel As Boolean)
Application.Calculation = xlCalculationAutomatic
End Sub

If you are not familiar with VBA this will be a little difficult but not too much!