Some say that it has something to do with too many fonts, but he only has 300 fonts. I have scoured the internet for a solution to this problem.
When he clicks 'ok', the message immediately pops up again. Then, you can restart Outlook and attach the file to the message again.' Then a following message that says the draft message couldn't be saved.
Intermittently, when he attempts to attach a file to an email, before he can send the email he gets an error message that says 'Outlook can't send or save this message with the attached file If you remove the attachment, you will be able to save the draft message. I am supporting a client who is using Microsoft Outlook 2016 version 16.21 on a Mac with Mojave.
