I have researched your database but unable to find a scenario that resembles mine.   When I go to the source of my attachment like for example the pictures folder and select picture to attach then share by selecting email Windows Live Mail the email form comes up with the attachment.  The problem starts when I click send it stays in the outbox.  The you click send again your get an error message.  When I clear my outbox of the mail and create new mail and attach the data it sends just fine.  It is only when I go to the source attachment location and attach and share through email and send it stays in the outbox.  I am using Window 10 & Windows Live Mail essentials.  I appreciate any insights you may have.  Thank you.