That is correct. What is the issue?

Sorry, I should have provided more info. When I attach a .pdf file ready to send to a client I always like to check the file I'm sending. My usual process is to open the attachment prior to sending. So by double clicking on the attachment or using the open command nothing happens. Adobe Reader doesn't fire up. This is only a recent issue and became a problem after Adobe updated the reader to DC.

Thanks for looking into this !

On the toolbar > Options > Attachments > incoming and delete any entry listed there for a PDF file You can modify the helper, but I find deleting is less prone to human error.

Thank you ! Problem solved.