Today, I was reminded that many corporate email programs are configured to remove attachments from incoming emails. I had sent one with attachments that were important parts of the contents, but were not received by my recipient.
Attachments are most often removed for security reasons. The solution to this problem is to copy and paste those items directly into the main body of the email so that there are no attachments, just the mail itself, and then your recipient will receive what you sent, and it will not be removed by a security feature.
And this applies to other operating systems as well as Windows. It's an email thing, not related to your operating system itself.