VBA - protect sheet and allow grouping/ungrouping (outline)

[Aussiebear]

You need to unprotect the shared workbook first. The code below is a simplified stand alone version.

Sub Unprotect_Sheet()
    ActiveWorkbook.UnprotectSharing "YourPassword”
End Sub

In your case you might like to try

Private Sub workbook_open()
Dim ws As Worksheet
For Each ws In ActiveWorkbook.Sheets
    ws.Protect Password:="password", SharingPassword:= "SharedPassword", userinterfaceonly:=True, _
    AllowFormattingCells:=True, _
            AllowFormattingColumns:=True, _
            DrawingObjects:=False, _
            Contents:=True
    ws.EnableOutlining = True
    ws.EnableAutoFilter = True
Next End Sub