Read Messages Suddenly Become Unread
TBird Version 91.4.1, Windows 10. Occasionally when I start TBird, a lot of messages that were read a long time previously are suddenly highlighted as unread. Also, Mark folder read doesn't mark the subfolders. So, to stop them from being highlighted, I have to descend to the lowest folder level and mark each one as read.
Alle antwurden (2)
is your account IMAP?
No, POP. The messages had been downloaded a long time previously. But suddenly TBird marked them as unread.