PrivateSub runOnOpen

    Call openExcel
    Call UpdateAllFields


End Sub

Sub openExcel()

  Dim excelApp As Excel.Application
  Dim openExcel As Workbook
  Dim var1 As Integer

  Set excelApp = New Excel.Application
  Set openExcel = excelApp.Workbooks.Open("filename")
  excelApp.Visible = True

End Sub

Sub UpdateAllFields()

    Application.DisplayAlerts = False
    ActiveDocument.Fields.Update
    Application.DisplayAlerts = True

End Sub