Why do I get false new mail alerts when I know that I have no new mail?
Even after I have read all new mail and deleted those I do not want to save from the server, I get a new mail notification. This has been going on for a few years now, however quite some time ago it did not happen. I have a suspicion that when Thunderbird does a mail check and there has been a recent deletion of mail, it registers as new mail. Seems it may be confused on the direction of the mail with regard to the mail server.
Alla svar (1)
You're confident that there are no new messages that went directly to Trash or Junk, or were moved by a filter?
Does View|Folders|Unread show up any unread messages hiding in unexpected places?