Using older versions of Outlook for Mac for personal email and calendar
Yep, tag i'm it....
I changed to a new mac and this started happening to me as well. The old mac is fine - so definitely not a subscription problem - or a version of outlook/ or mac os (all the same) .... its some sort of mashup of programs and install order or methods.
I see it mostly PDF files but Word files also happening as well..... but seems to be when i attach OneDrive files - as opposed to files on my local computer... so maybe a problem with onedrive files being added and linked to the sending email from outlook.
As others have mentioned - I can't have this inconsistency when trying to work.. Embarrassing and time wasting..
Help fix the Microsoft.