VBA to filter multiple sheets

Hi All,

I have a macro that filters all the sheets in a workbook based on a cell entry on sheet 1. The filter runs through Columns 1.

This works quite well(other than flicker issues).

The problem is I also need the filter to run through column K and show rows that have an empty cell.(i.e UnInvoiced) I have tried the below code, but it shows the empty formula rows below all data not the uninvoiced rows.

ElseIf RLetter = "Uninvoiced" And w.AutoFilterMode Then
w.Unprotect Password:="test"
w.Range("K3").AutoFilter Field:=11, Criteria1:=""

Please Help

Cheers

Adam