Pivot Table Filter Macro Not working

I am trying to speed up a pivot table filter of over 15000 items.

I have been advised to add the code line "pt.ManualUpdate=True" which is now preventing it from running at all - Runtime Error 91, Object variable or With block variable not set.

Has anyone got any suggestions of how to fix it but get the filter to run quickly, without any modification it takes around 4 mins to filter the report.

Sub openfilter()
'
' openfile Macro
'
    Dim Pf As PivotField
    Dim Pi As PivotItem
    Dim pt As PivotTable
        
    Sheets("Mile").Select
    ActiveWindow.SmallScroll Down:=-21
    ActiveWorkbook.ShowPivotTableFieldList = False
    ActiveWindow.SmallScroll Down:=-270
    Application.ScreenUpdating = False
    'Application.Calculation = xlManual
    'ActiveSheet.PivotTables("PivotTable3").ManualUpdate = True


    'Application.DisplayAlerts = False
    
       
    Set Pf = ActiveSheet.PivotTables("PivotTable3").PivotFields("Name")
'Fault on the next line...
pt.ManualUpdate = True

   
    'Pf.ClearAllFilters
   
    With Pf
       For Each Pi In .PivotItems
           If Not (Pi.Caption Like "Dave") Then
                Pi.Visible = False

           End If
       Next Pi
     End With
     
pt.ManualUpdate = False
    
Application.ScreenUpdating = True

End Sub

Solved. Thanks MRice