If you already have the outline applied, you can protect the worksheet in code
(auto_open/workbook_open??).

Option Explicit
Sub auto_open()
With Worksheets("sheet1")
.Protect Password:="hi", userinterfaceonly:=True
.EnableOutlining = True
End With
End Sub

It needs to be reset each time you open the workbook. (excel doesn't remember
it after closing the workbook.)

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm

David wrote:

I'm using Excel 2002 and would like to protect a worksheet containing an
outline. I can protect the sheet, but then cannot use the outline buttons. Is
there any way around this?
TIA
--
David

--

Dave Peterson