Using older versions of Outlook for Mac for personal email and calendar
Same here - the only thing for now (to my knowledge) is to revert to the old outlook and wait until Microsoft issues a fix which is expected in August. Most of the time (using new outlook which I used for years with no issue) it removes all attachments upon send then will deliver the attachments upon my second attempt. I've also had it remove 1 of 2 attachments, for whatever reason letting the other go through. Certainly makes you look like a moron to your clients and looking forward to it being fixed.