Cryptic pushed out a little mini-patch this morning, specifically to address the little mail “incident” from yesterday’s patch. All your attachments should now be visible in the mail, hopefully, you didn’t delete the message thinking it was empty ;)
Release notes from today’s minipatch:
Attachments have been returned to all in game mails that had them and players have access to them again.
The number of items in a stack does not appear on the item icon that appears in the mail.