I would not use an Autofilter on large data sets as they can take quite a bit of time trying to enumerate the available options before actually filtering the data. The AutoFilter.ShowAllData takes just as much time. For my super simple test dataset, which consisted of 26 columns of 1000000 rows, it took 30+ seconds for each to process.
From what I can tell you are filtering the list to show only the blank items and then deleting the blank rows. Since the filtering is what is causing the delay we could just loop through each row looking at a specific column and if it is blank you can just delete it. Below is an example of how to do this.
**Edit: After testing I found this to be much slower than what you would want. Check out the next example below as it is super fast.
Option Explicit
Sub DeleteBlank()
Application.ScreenUpdating = False
Dim calcType As Integer
Dim rowCount, columnNumToCheck, currow, dataStartRow As Long
Dim WkSht As String
Dim lo As ListObject
WkSht = "BOM 6061" 'The name of the worksheet where the table is located.
columnNumToCheck = 17 'The column number to check for blank cells.
calcType = Application.Calculation
Application.Calculation = xlCalculationManual
Set lo = Sheets(WkSht).ListObjects(1)
rowCount = lo.ListRows.Count
dataStartRow = (lo.DataBodyRange.Row - 1)
For currow = rowCount To 1 Step -1
If Sheets(WkSht).Cells((currow + dataStartRow), columnNumToCheck).Value = "" Then
Call DeleteRows(WkSht, (currow + dataStartRow))
End If
Next currow
Application.Calculation = calcType
Application.ScreenUpdating = True
End Sub
Private Sub DeleteRows(sheetNameIn As String, startRow As Long, Optional optionalEndRow As Long)
If IsNull(optionalEndRow) Or optionalEndRow = 0 Then
optionalEndRow = startRow
End If
Worksheets(sheetNameIn).Range(startRow & ":" & optionalEndRow).Delete Shift:=xlUp
End Sub
If you are able to sort your data where the blank cells are all together you could use the below to perform a single delete function remove them all at once. This deleted 70000 rows in a few seconds.
Sub DeleteBlankWithSort()
'Application.ScreenUpdating = False
Dim columnNumToCheck, tableLastRow, lrow As Long
Dim calcType As Integer
Dim WkSht As String
Dim lo As ListObject
WkSht = "BOM 6061" 'The name of the worksheet where the table is located.
columnNumToCheck = 17 'The column number to check for blank cells.
calcType = Application.Calculation
Application.Calculation = xlCalculationManual
Set lo = Sheets(WkSht).ListObjects(1)
tableLastRow = FindLastRow(WkSht, (columnNumToCheck))
With lo.Sort
.SortFields.Clear
.SortFields.Add _
Key:=Range("Table1[[#All],[q]]"), _
SortOn:=xlSortOnValues, _
Order:=xlDescending, _
DataOption:=xlSortNormal
.Header = xlYes
.MatchCase = False
.Orientation = xlTopToBottom
.SortMethod = xlPinYin
.Apply
End With
lrow = FindLastRow(WkSht, (columnNumToCheck), (tableLastRow))
Call DeleteRows(WkSht, (tableLastRow), (lrow + 1))
Application.Calculation = calcType
Application.ScreenUpdating = True
End Sub
Private Sub DeleteRows(sheetNameIn As String, startRow As Long, Optional optionalEndRow As Long)
If IsNull(optionalEndRow) Or optionalEndRow = 0 Then
optionalEndRow = startRow
End If
Worksheets(sheetNameIn).Range(startRow & ":" & optionalEndRow).Delete Shift:=xlUp
End Sub
Private Function FindLastRow(sheetNameIn As String, columnNum As Long, Optional optionalStartRow As Long) As Long
'finds the last row of the column passed in the sheetname passed in
If IsNull(optionalStartRow) Or optionalStartRow = 0 Then
optionalStartRow = 1048576
End If
FindLastRow = Worksheets(sheetNameIn).Range(Cells(optionalStartRow, columnNum).Address).End(xlUp).Row
End Function