Looping "Batch Export" Crashes - Processor or Code Error? - excel

Question

Why can't Excel loop through large datasets?!
I have 2 different document forms which need to be exported to PDF by the hundreds. I pulled the batch export script from the internet and modified it for my usage so it would process either of these forms depending on the checkbox selected on the "Batch PDF Printer" worksheet.
Everything runs well - for the first 10-15 workbooks accessed by the loop, and then it crashes. Every Excel document freezes (Not Responding) and the page that is currently accessed by the Macro partially opens with no visible data or cells. The "Publishing" message box may also freeze at this point. Once it reported a lack of memory error - but I have not been able to repeat this. Shouldn't Excel be deleting unused cache's so as to not overload the memory? I would suspect a bum loop if it didn't run well for a while. I've heard there is no way to script in a "cache dump" or something of that nature. Is it bad code, or am I asking too much of my processor?
Sub Convert2PDF()
'Update the checkbox linked formulas on the GUI workbook
Sheet1.Range("A2").Formula = Sheet1.Range("A2").Formula
Sheet1.Range("B2").Formula = Sheet1.Range("B2").Formula
Sheet1.Range("C2").Formula = Sheet1.Range("C2").Formula
Dim strFolder As String
Dim strXLFile As String
Dim strPDFFile As String
Dim wbk As Workbook
Dim lngPos As Long
' set folder
strFolder = ThisWorkbook.Path & "\putfileshere" & "\"
Application.ScreenUpdating = False
' Get first filename
strXLFile = Dir(strFolder & "*.xls*")
' Loop through Excel workbooks in folder
Do While strXLFile <> ""
' Open workbook
Set wbk = Workbooks.Open(Filename:=strFolder & strXLFile)
' Assemble the PDF filename
lngPos = InStrRev(strXLFile, ".")
strPDFFile = Left(strXLFile, lngPos) & "pdf"
' Export to PDF
'Do the next 8 lines crash the Macro because they recalculate for every sheet? Page1, Page2, Page3 value are the same for all workbooks processed in a batch
Dim Page1 As String
Dim Page2 As String
Dim Page3 As String
Dim Page4 As String
Page1 = ThisWorkbook.Sheets("Batch PDF Printer").Range("A2")
Page2 = ThisWorkbook.Sheets("Batch PDF Printer").Range("B2")
Page3 = ThisWorkbook.Sheets("Batch PDF Printer").Range("C2")
If ThisWorkbook.Sheets("Batch PDF Printer").Range("C2") = "" Then
wbk.Sheets(Array(Page1, Page2)).Select
ActiveSheet.ExportAsFixedFormat Type:=xlTypePDF, Filename:= _
ThisWorkbook.Path & "\pdfsgohere" & "\" & wbk.Name, _
Quality:=xlQualityStandard, IncludeDocProperties:=False, _
IgnorePrintAreas:=False, OpenAfterPublish:=False
'run process for format option 2
Else:
wbk.Sheets(Array(Page1, Page2, Page3)).Select
ActiveSheet.ExportAsFixedFormat Type:=xlTypePDF, Filename:= _
ThisWorkbook.Path & "\pdfsgohere" & "\" & wbk.Name, _
Quality:=xlQualityStandard, IncludeDocProperties:=False, _
IgnorePrintAreas:=False, OpenAfterPublish:=False
'Tried killing the finished document to improve function
Dim xFullName As String
xFullName = Application.ActiveWorkbook.FullName
ActiveWorkbook.Saved = True
Application.ActiveWorkbook.ChangeFileAccess xlReadOnly
Kill xFullName
Application.ActiveWorkbook.Close False
End If
' Close workbook - didn't seem to help (can't do it when the workbook is gone)
'wbk.Close SaveChanges:=False
' Get next filename
strXLFile = Dir
Loop
Application.ScreenUpdating = True
MsgBox "All Done"
Thanks for the help. I've been trying to figure this out for days now.

Answer 1

This ran for me on >30 files with no problem:
Sub Convert2PDF()
Dim strFolder As String, strXLFile As String
Dim strPDFFile As String
Dim wbk As Workbook
Dim lngPos As Long
Dim pages(1 To 4) As String
Dim shtBatch As Worksheet, arr
Set shtBatch = ThisWorkbook.Sheets("Batch PDF Printer")
shtBatch.Range("A2:C2").Calculate '<< assume this was the point of resetting the formulas?
pages(1) = shtBatch.Range("A2").Value
pages(2) = shtBatch.Range("B2").Value
pages(3) = shtBatch.Range("C2").Value
'what pages to print? Only need to do this once
arr = IIf(Len(pages(3)) = 0, Array(pages(1), pages(2)), _
Array(pages(1), pages(2), pages(3)))
strFolder = ThisWorkbook.Path & "\putfileshere\"
strXLFile = Dir(strFolder & "*.xls*")
Do While strXLFile <> ""
Set wbk = Workbooks.Open(Filename:=strFolder & strXLFile, ReadOnly:=True)
lngPos = InStrRev(strXLFile, ".")
strPDFFile = Left(strXLFile, lngPos) & "pdf"
wbk.Sheets(arr).Select
ActiveSheet.ExportAsFixedFormat Type:=xlTypePDF, _
Filename:=ThisWorkbook.Path & "\pdfsgohere\" & strPDFFile, _
Quality:=xlQualityStandard, IncludeDocProperties:=False, _
IgnorePrintAreas:=False, OpenAfterPublish:=False
wbk.Close False
strXLFile = Dir
Loop
MsgBox "All Done"
End Sub

Answer 2

Even if your visible system RAM is not overloading, the internal capacity of the Excel application seems to be exceeded for a brief moment. I was able to finally view the message box "Not enough system resources to display completely" before the app went into automatic reboot. Try streamlining the workbooks being accessed by the loop. If your workbooks take a while to start up, that may be indication of heavy background processes (calculations and VBA subs). DoEvents may help the code run more smoothly by asking for more processing time so the system can sort it's demands. Ultimately,
Application.Calculation = xlManual
at the top of the loop was sufficient to reduce the computational demands on the 20 gig system (which I never expected to overload).

Answer 3

If you have linked images in your exports.
Exported linked images leaves behind a bit or byte in the kernel, which accumulates and eventually breaks excel.
I found this solution only 1 place on the internet and i cannot find it again, but it got me from 200s to 1000 loops of VBA Macro by removing linked images.
Nothing in the VBA code would help, i used pauses, save the workbook to clear memory, disable events etc...
I wrote an answer to my problem here: https://stackoverflow.com/a/53600884/10069870
Disregard if you have no linked images in your exports :)