Hi
I had numerous false paths for people and genres in my databse after upgrading to V4 (see https://emby.media/community/index.php?/topic/71572-upgraded-to-v-403-have-some-problems/page-2 for my original problem). For people this was in the thousands and far too complex to fix using SQL edit via DB view. So I renamed my library.db to library.db.old to delete my library database and did a rescan.
All looks better after this but watched status was not restored. Each NFO for a watched mov