Unbelievable. Outreageous. No support. No admitting your ridiculous customer service is pathetic.
Emails come through your system to my Macintosh's email folder (I use Apple Mail as my app) but don't appear in my Xfinity email window. In today's edition of Comcast Madness, an email arrived from a client with an important PDF attached, attached both straight and Zipped. Both attachments show zero data. The email, even though it came through your servers to my house, is missing in my Xfinity email window. This has gone far beyound ridiculous. I refuse to ever again waste my time in a "chat" with someone in another country who's only answer is to "reload your Outlook." Your phone help is no better, I get uninformed people who have no idea what I'm talking about and, of course, want me to... reload my Outlook.
Is your Mac's mail using POP3 or IMAP? If it's set to POP3, it will usually delete the mail from the Xfinity server after downloading it.
I prefer POP3 (I only use my production MacPro tower for email, I do not receive email on my Android phone nor on any of my other PCs and Macs) but Comcast seems to only allow me to use IMAP when I create new logins. I also have my Xfinity email browser (Firefox) set manually to retain all emails, and I've had that setting for years. I'm now asking my clients to use services like WeTransfer for file transfers. As far as I can tell, even though the files still arrive through Comcast's ancient coax cable running along the telephone poles in my block's back yards, Comcast doesn't seem to feel the need to mess around with the contents of the files.