Replace Method Generates Application-Defined or Object-Defined Error in Excel for Mac

I'm having trouble with this on the latest version of Excel for Mac.

Here's the macro:

Sub Run()
'
' Run Macro
'

'
    Sheets("Data").Select
    Cells.Select
    Range("BK1").Activate
    Selection.Replace What:="unknown", Replacement:="", LookAt:=xlPart, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False

    Sheets("Pivot Table").Select
    ActiveSheet.PivotTables("PivotTable1").PivotCache.Refresh
    ActiveSheet.PivotTables("PivotTable2").PivotCache.Refresh
    ActiveSheet.PivotTables("PivotTable3").PivotCache.Refresh
    ActiveSheet.PivotTables("PivotTable4").PivotCache.Refresh
    Sheets("Formatted Data").Select
    ActiveWorkbook.Worksheets("Formatted Data").AutoFilter.Sort.SortFields.Clear
    ActiveWorkbook.Worksheets("Formatted Data").AutoFilter.Sort.SortFields.Add Key _
        :=Range("A4"), SortOn:=xlSortOnValues, Order:=xlDescending, DataOption:= _
        xlSortNormal
    With ActiveWorkbook.Worksheets("Formatted Data").AutoFilter.Sort
        .Header = xlYes
        .MatchCase = False
        .Orientation = xlTopToBottom
        .SortMethod = xlPinYin
        .Apply
    End With



End Sub

When I run it, I get a MSFT Visual Basic error:

 Run-time error '1004':

 Application-defined or object-defined error

If I remove this part, it runs fine, but isn't exactly what I need in terms of final result:

Sheets("Data").Select
    Cells.Select
    Range("BK1").Activate
    Selection.Replace What:="unknown", Replacement:="", LookAt:=xlPart, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False

UPDATE

If I remove just this little part, the macro runs, but not sure if I lose anything by removing this:

SearchFormat:=False, _
    ReplaceFormat:=False