Elements Organizer 2019

Just bought and installed Premier Elements 2019.  I have all my multimedia files on an NAS in one folder "Photos" which contains msny sub folders by date.  I did a clean install and imported the NAS file "Photos".  All photos in organizer correctly but video files mostly MOV files from iPhone only about 2/3 show thumbnails and play correctly but after a certain date in 2018 show only a filmstrip image and when clicked on to play come up " media pending".  It has been 24 hours and I am uncertain if it is still indexing or what is going on.  Everything else works fine.

Any ideas how to get the remaining videos thumbnails to populate and play in the organizer?