I have covered this, and how to avoid duplicate names etc., several times in this forum. However the following should work with your code.
Sub ProcessAllMessagesInFolder()'Graham Mayor - https://www.gmayor.com - Last updated - 23 Oct 2019
Dim olItems As Outlook.items
Dim olItem As Object
Dim sPath As String
Set olItems = Session.PickFolder.items
For Each olItem In olItems
If TypeName(olItem) = "MailItem" Then
saveAttachtoDisk olItem
End If
DoEvents
Next olItem
lbl_Exit:
Set olItem = Nothing
Set olItems = Nothing
Exit Sub
End Sub