Hi Chris,

the best way to send mail only if the to-be-attached file isn't empty
is... not to create empty files... :) Have you considered such an
alternative?
Actually you don't need to be in data flow to check if data exists,
yes this can be easier performed in data flow, but with the script
task in control flow you could figure it out.
In fact I thought about Script Task, which you can use not only to
check for data inside the record but also to send the mail.
Through coding you can check and send only the most recent files, or
the files bigger than 0bytes...

HTH,
M.