Not all mail items are saved when using subject as file name - vba

Question

I obtained the code from a tutorial online.
I tested it and updated variables specific to my local system.
There is a problem with the export.
Previously, I ran the code successfully.
All 128 items of the Outlook folder were obtained.
There are now 231 items in the Outlook folder.
The code repeatedly only obtains 162.
I can confirm;
all items are mail (not meeting or read receipts)
the 162 items obtained contains attachments - so it is not a limit on this basis
I refreshed and sync'd Outlook exchange with local machine several times.
previously, one mail item contained *** in the title. This broke the code, I adapted it as can be seen, and it ran without issue.
I considered
mail items are of a type that I have not defined?
there is an issue with the titles of the other mail items?
this code is limited by memory allocation?
the problem is the sync between Outlook exchange and local device
Sub ZipAllEmailsInAFolder()
Dim objFolder As Outlook.Folder
Dim objItem As Object
Dim objMail As Outlook.MailItem
Dim strSubject As String
Dim varTempFolder As Variant
Dim varZipFile As Variant
Dim objShell As Object
Dim objFileSystem As Object
'Select an Outlook Folder
Set objFolder = Outlook.Application.Session.PickFolder
If Not (objFolder Is Nothing) Then
'Create a temp folder
varTempFolder = "C:\Users\thomdenm\Music\" & objFolder.Name & Format(Now, "YYMMDDHHMMSS")
MkDir (varTempFolder)
varTempFolder = varTempFolder & "\"
'Save each email as msg file
For Each objItem In objFolder.Items
If TypeOf objItem Is MailItem Then
Set objMail = objItem
strSubject = objMail.Subject
strSubject = Replace(strSubject, "/", " ")
strSubject = Replace(strSubject, "\", " ")
strSubject = Replace(strSubject, ":", "")
strSubject = Replace(strSubject, "?", " ")
strSubject = Replace(strSubject, Chr(34), " ")
strSubject = Replace(strSubject, "*", " ")
objMail.SaveAs varTempFolder & strSubject & ".msg", olMSG
End If
Next
'Create a new ZIP file
varZipFile = "C:\Users\thomdenm\Music\" & objFolder.Name & " Emails.zip"
Open varZipFile For Output As #1
Print #1, Chr$(80) & Chr$(75) & Chr$(5) & Chr$(6) & String(18, 0)
Close #1
'Add the exported msg files to the ZIP file
Set objShell = CreateObject("Shell.Application")
objShell.NameSpace(varZipFile).CopyHere objShell.NameSpace(varTempFolder).Items
On Error Resume Next
Do Until objShell.NameSpace(varZipFile).Items.Count = objShell.NameSpace(varTempFolder).Items.Count
Application.Wait (Now + TimeValue("0:00:01"))
Loop
On Error GoTo 0
'Delete the temp folder
Set objFileSystem = CreateObject("Scripting.FileSystemObject")
objFileSystem.DeleteFolder Left(varTempFolder, Len(varTempFolder) - 1)
End If
End Sub

Answer 1

First of all, I'd remove the condition where you check for the item type or add others to make sure all items are processed. Or just add a counter to see how much items were checked through.
counter = counter+1
If TypeOf objItem Is MailItem Then
Second, the On Error statement can help you identify the source of the problem if any error comes in.
Third, it makes sense to split the logic where you get Outlook items and save them to a folder. The other piece of code can be extracted to a separate method , so following this way you can easily be sure that one or another method works correctly (the Outlook-related part).
And, finally, the most important thing is that items can belong to the same conversation and have identical subject line which can lead to overwriting saved items in the folder. Is this the case?
objMail.SaveAs varTempFolder & strSubject & ".msg", olMSG
I'd recommend adding any ID to the file name so you can be sure no items are overwritten in the folder. For example, it can be current time or milliseconds and etc.