When new emails are received they are marked as Unread for a while, but after a time, will be marked as Read. This would occur whether I looked at any emails or not. The program is running in the background, but not accessed. I have used Thunderbird in the past with a POP account, but a couple months ago converted to IMAP. This is when the problem started. Under Preferences - Reading & Display, the "Automatically mark messages as read" option is NOT CHECKED. I don't want to abandon Thunderbird. Thank you to anyone who can assist.