It seems I'm having the same issue as many other people after performing an update (Version 1.0.3.2461).
I get this message, "There was an unexpected error loading the dashboard"
Also getting "Media not found. - The media you're trying to access doesn't seem to exist." in my TV Shows, but for some reason Movies are still working fine.
I've followed https://forums.plex.tv/discussion/comment/1184161/#Comment_1184161, but I get the error, "There was a problem optimizing the database".
Is there a solution to this problem?