Outlook and VFP

In my accounting system, clients can email their clients an invoice or copy of an invoice. It places the message and pdf into Outlook. Outlook then takes care of it, and you can all such emails in the Sent folder This has worked for years!

I now have a client who has shown me her Sent folder and I can see dozens of entries where it has sent the email, but no attachment.

Can anyone suggest how this can happen?

My accounting system also has a "sent" emails dbf and it shows these emails were placed in to Outlook and the fact there was an attachment (or not)