VBA for each loop with 64K+ ListRows (ouf of memory) - excel

Question

I'm running a VBA for each loop through an Excel table (Listobject) which checks if a file exists based on a given path. My table has expanded though and has 68K Listrows. After launching the code, it quickly gives an error Run-time-error '7': Out of memory
It runs OK with 63K lines (done within 5 minutes) and based on googling there appears to be something called "64K segment boundary". Is this what's affecting my code to run since it really feels like it buffers the row count at first and then bounces back w/o starting to actually run anything. Is there an easy workaround for this without the need to split up my dataset into multiple batches? Frankly, I was quite surprised that 64K limits would still be a thing in Excel in 2021.
Running it on 64bit Excel 2019, but no luck with Office365 either.
Sub CheckFiles()
Dim Headers As ListObject
Dim lstrw As ListRow
Dim strFileName As String
Dim strFileExists As String
Application.ScreenUpdating = False
Set ws = ThisWorkbook.Sheets("Import")
Set Headers = ws.ListObjects("Import")
For Each lstrw In Headers.ListRows
strFileName = lstrw.Range(7)
strFileExists = Dir(strFileName)
If strFileExists = "" Then
lstrw.Range(4) = "not found"
Else
lstrw.Range(4) = "exists"
End If
Next lstrw
Set ws = Nothing
Set Headers = Nothing
Application.ScreenUpdating = True
End Sub

Answer 1

Avoid Accessing the Worksheet
Since you cannot avoid looping, you better do it in the computer's memory, i.e. rather through the elements of an array than through the cells of a range.
The code is still slow, about 10s for 200k rows on my machine, but that's because of Dir.
Note how easy (one line only, when the range contains more than one cell) and how fast (a split second) it is to write (copy) a range to an array (Data = rg.Value) and write (copy) the array back to a range (rg.Value = Data).
Adjust the values in the constants section.
Option Explicit
Sub CheckFiles()
Const wsName As String = "Import" ' Worksheet Name
Const tblName As String = "Import" ' Table Name
Const cCol As Long = 7 ' Criteria Column
Const dCol As Long = 4 ' Destination Column
Dim wb As Workbook: Set wb = ThisWorkbook
Dim ws As Worksheet: Set ws = wb.Worksheets(wsName)
Dim Headers As ListObject: Set Headers = ws.ListObjects(tblName)
Dim Data As Variant ' Data Array
With Headers.ListColumns(cCol).DataBodyRange
If .Rows.Count = 1 Then
ReDim Data(1 To 1, 1 To 1): Data = .Value
Else
Data = .Value
End If
End With
Dim r As Long ' Array Row Counter (DataBodyRange Row Counter)
Dim FileName As String ' File Name Retrieved by Dir
For r = 1 To UBound(Data, 1)
FileName = Dir(CStr(Data(r, 1)))
If Len(FileName) = 0 Then
Data(r, 1) = "not found"
Else
Data(r, 1) = "exists"
End If
Next r
Headers.ListColumns(dCol).DataBodyRange.Value = Data
End Sub

Answer 2

Thank you all! A few takeaways. While obviously trying to write as efficient code as possible, any reasonable performance here is acceptable. With that said, for each loop took approx 5 minutes to run with 63K lines, meawhile it was done in about 15 seconds by the code I accepted as an answer by #VBasic2008 - without capacity problems either.
The only problem I had with this particular code was it being somewhat new approach for me, so possibly building on it in the future needs some dedication in looking deeper into it - but it sure looks efficient. I also put together a regular for ... to loop which also didn't run into problems with 68K lines and would steer between rows and columns with offset function.
Clearly faster than for each as #Pᴇʜ suggested but took approx 2x as long as the array method (30 seconds or so).
Sub CheckFiles_2()
Dim strFileName, strFileExists As String
Dim ws As Worksheet
Dim Headers As ListObject
Dim result As String
Dim counter, RowCount As Long
Application.ScreenUpdating = False
Set ws = ThisWorkbook.Sheets("Import")
Set Headers = ws.ListObjects("Import")
RowCount = Headers.ListRows.Count
For counter = 1 To RowCount
strFileName = Range("anchorCell").Offset(counter, 3)
strFileExists = Dir(strFileName)
If strFileExists = "" Then
result = "not found"
Else
result = "exists"
End If
Range("anchorCell").Offset(counter, 0) = result
Next counter
Set ws = Nothing
Set Headers = Nothing
Application.ScreenUpdating = True
End Sub