Filldown VBA not working

[TP700]

Hello, I have some coding which filters some columns to find data I need to add a comment against, then writes the comment and fills it down to the bottom. However, the Filldown isn't working. Everything works fine up until that point, once it gets to the Selection.filldown, it just doesn't do anything, there is no error message it just doesn't do anything. Any ideas what I am missing? Thanks

Sub Description()

Dim lastRow As Long
lastRow = Cells(Rows.Count, "AB").End(xlUp).Row

Range("AB1:AB" & lastRow).Offset(1, 0).SpecialCells(xlCellTypeVisible).Areas(1).Rows(1).Select

Sheets("Data").Select
Cells.Select
Application.CutCopyMode = False
Selection.Copy
Sheets.Add After:=ActiveSheet
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Cells.Select
Cells.EntireColumn.AutoFit
Columns("D:D").Select
Application.CutCopyMode = False
Selection.Delete Shift:=xlToLeft
Range("O1").Select
Selection.AutoFilter
ActiveWorkbook.Worksheets("Sheet2").AutoFilter.Sort.SortFields.Clear
ActiveWorkbook.Worksheets("Sheet2").AutoFilter.Sort.SortFields.Add2 Key:= _
Range("O1:O58100"), SortOn:=xlSortOnValues, Order:=xlAscending, DataOption _
:=xlSortNormal
With ActiveWorkbook.Worksheets("Sheet2").AutoFilter.Sort
.Header = xlYes
.MatchCase = False
.Orientation = xlTopToBottom
.SortMethod = xlPinYin
.Apply
End With
ActiveSheet.Range("$A$1:$BK100000").AutoFilter Field:=15, Criteria1:= _
"Required"
ActiveSheet.Range("$A$1:$BK100000").AutoFilter Field:=28, Criteria1:= _
""

Range("AB1:AB" & lastRow).Offset(1, 0).SpecialCells(xlCellTypeVisible).Areas(1).Rows(1).Select

ActiveCell.FormulaR1C1 = "Completed"

Range("AB1:AB" & lastRow).Offset(1, 0).SpecialCells(xlCellTypeVisible).Areas(1).Rows(1).Select
Selection.filldown

End Sub

[#2]

@TP700 

The instruction

Range("AB1:AB" & lastRow).Offset(1, 0).SpecialCells(xlCellTypeVisible).Areas(1).Rows(1).Select

selects a single cell. So there is nothing to fill down.

[#3]

What would I need to replace this with in order to make it fill down?

[#4]

@TP700 

Please explain what you want to do - it's difficult to follow the code.

[#5]

So I want it to Enter "Completed" in the top cell (which it does) and then copy that down to the bottom, so all of those blanks filled with "Completed"

[#6]

@TP700 

Does this work?

Sub Description()
    Dim w1 As Worksheet
    Dim w2 As Worksheet
    Dim lastRow As Long
    Application.ScreenUpdating = False
    Set w1 = Worksheets("Data")
    w1.Cells.Copy
    Set w2 = Worksheets.Add(After:=w1)
    w2.Range("A1").PasteSpecial Paste:=xlPasteValues
    lastRow = w2.Cells(w2.Rows.Count, "AB").End(xlUp).Row
    Application.CutCopyMode = False
    w2.Cells.EntireColumn.AutoFit
    w2.Columns("D:D").Delete Shift:=xlToLeft
    w2.Range("O1").AutoFilter
    With w2.AutoFilter.Sort
        .SortFields.Clear
        .SortFields.Add2 Key:=Range("O1"), SortOn:=xlSortOnValues, _
            Order:=xlAscending, DataOption:=xlSortNormal
        .Header = xlYes
        .MatchCase = False
        .Orientation = xlTopToBottom
        .Apply
    End With
    w2.Range("$A$1:$BK100000").AutoFilter Field:=15, Criteria1:="Required"
    w2.Range("$A$1:$BK100000").AutoFilter Field:=28, Criteria1:=""
    w2.Range("AB2:AB" & lastRow).SpecialCells(xlCellTypeVisible).Value = "Completed"
    Application.ScreenUpdating = True
End Sub