It appears that you have a message/messages stuck in All News.
Possible solution - If you are confident at editing the Registry.
I would suggest rebuilding your Quick views by deleting (with WLMail closed) the registry value SearchFolderVersion at HKCU\Software\Microsoft\Windows Live Mail.
It looks like there's some discrepancy between messages the MessageStore thinks you have and the ones you actually have. Restarting WLMail will take a little longer while the Quick view database is rebuilt.