Email attachement not working

I spent hours yesterday in front of my computer while Adobe tried to resolve my issue.
When I click on the envelope to attach the document to an email the file closes and so does the programme. So I am having to save the doument and then attach it to an email.
I went to files. I unchecked the box in account settings for Cached Exchange Mode but that made no difference.

I am also getting a blue box in top right hand corner saying your last session ended abruptly, click restore to reopen the PDF's from the last session.