The issue persists on multiple computers, so it's not limited to my install.
I am receiving PDF attachments from other senders - but things only go wrong when the mail originates from an October CMS install. Please be advised that there are multiple users that state that they can not receive any PDF attachments in Windows 10 Mail from any sender but this isn't the case for me. This gives me the impression something might be wrong in the internals of the mail system. When sending the original e-mail to Gmail for example (where the PDF does show up without issue), and then forwarding it to Windows 10 Mail, the attachment does show up. but for some reason it never shows up in the native Windows 10 Mail client. It does show up in Outlook, Gmail, Outlook Online. When sending an e-mail with a PDF attachment, the attachment doesn't show up in Windows 10 Mail.
