I have overcome it by choosing (in Explorer) "Compatibilty View Settings" (under Tools Menu) after pushing the "Unread Posts". Then after changing the status ("Add" or "remove" and depress "Close") ,the problem is normally fixed until next time.
I'm having this problem now, have been for the past few months. The only way I get around it is to delete all of my settings and starting fresh, but that means re-entering all of my passwords to all of my sites and resetting all of my bookmarks and saved pages. What a hassle. So I just don't use the unread posts anymore