I have an odd issue where I received an email with an attached PDF file (from someone I know, trust, and was expecting the message from) but my Outlook 2016 email client claimed no attachment was present.
I started digging and noticed the problem email had a size consistent with an email containing the attached PDF file. So I exported it as a .msg file and viewed it on another computer with known clean Outlook settings. This client also reported no attachments.
So I opened the .msg file up in a hex editor (Frhed) and found the %PDF and %%EOF file headers and footers embedded in the exported .msg file. I extracted the PDF file and it opened fine, no corruption.
I routinely successfully receive email attachments including PDF attachments. I've even successfully received PDF email attachments from this same sender before.
I've checked for one of the usual culprits - RTF or plain text email formatting. Both ends have the default HTML email formatting and use Outlook.
Another recipient of the same message saw the PDF attachment just fine. This recipient was also using Outlook.
I haven't messed with my Outlook settings they should nearly all be default.
Before you ask.. no I cannot upload the .msg file due to the private information it contains.
I guess this is fairly low priority, it's not really impacting much and I haven't seen it happen since. But maybe someone out there has seen this before and can tell me what might cause it.