I wouldn't open the PDF in Acrobat if there is no email address. Why are you doing this?
Also, are you pausing at the email or sending without a dialog?
The reason is that we have to generate all the letters at once (usually around 50 letters). All the letters are being generated as PDF files (stores as reference). Letters to recipients with email addresses are automatically being attached to an email - there's a pause in this step, yes - just for double checking. Potentially I will skip the pause step when I'm done with the development - and I can see that that would help. Letter to recipients without email addresses have to be sent manually by regular mail - hence I open the PDF-files in Acrobat, ready for printing.
And just for your information I have completely changed the workflow now.
I guess you where right. That's where the problem was.
Thanks for you time and comment