Orphaned movies won't disappear

To save space on my 2TB SSD, I moved about 400GB of movies channels recorded to another drive on the server that Plex uses for its datastore. I figured it would be a good way to archive them. So right now Channels does not have access to them, I removed them from the datastore manually. The problem is that Channels still thinks they are there (they can't be played though). How can I get rid of the orphans in short of going into all 80 titles manually and removing them?

I don't believe this an option in the UI to do this in bulk, but you can manually do it through the server's API:

Brilliant, thank you! Worked perfect