You can't change the message, but you can stop them from selecting locked cells
on a protected sheet.

Option Explicit
Sub auto_open()
Dim wks As Worksheet
Set wks = Worksheets("sheet1")
With wks
.Protect password:="hi"
.EnableSelection = xlUnlockedCells
End With
End Sub

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


Rich wrote:

is their a way to create your own error message

have a work book with protected cells , can i get the default message to
read something like

you arre not authorised to alter this data

--

Dave Peterson