Elements 2020 thumbnails do not show photo, only hourglass

Elements 2020 organizer does not show photos in the thumbnails, only hourglass for photos after February 2022.  Have to enlarge to where there are only 4 or 8 photos in view.  Nothing new going on; same camera i have used to 10 years.  Photos from 2021 back to oldest display properly in thumbnail.  10 year old computer; Windows 10; 28,000 photos.