Success:
There are 2 files in the spool which is fewer than the trigger (250)
The files in E:\SmarterMail\Spool are new.
(We cannot open E:\Webs\mail-system\files\TestMailSpool-CurrentList.txt for reading, so at last run mail spool was empty.
Currently there are 2 files in E:\SmarterMail\Spool.)