Deleted files still appear on the video menu

My video files are stored on a synology DS412. There are four video files that I have deleted from the DS412. The titles still appear on the menu when viewing the files from the OSMC Kodi video, files selecting the DS412. How can remove the titles from the OSMC video menu? I am using a raspberry pi b to run the OSMC Kodi.

clean your libary

Or if it’s only a few files it’s sometimes quicker to just remove them from the library individually - highlight the entry, choose menu, manage, then remove from library.