Zoom representation does not work correctly

[default27975891fo5dct]

I use: 

Elements Organizer 17.0.0.0
Hoofdversie: 17.0 (20180830.m.125874)
Taalversie: 17.0 (20180830.m.125874)

Small representation of thumbnails does not work properly. Using little thumbnails some pictures are shown correct, others only grey with a hourglass. Changing to a greater size these grey-with-hourglass change to the correct picture, but back to smaller thumbnails they change again to grey-with-hourglass. This phenomenon is attached to specific pictures (correct and hourglass-representation of the same camera, same day, same hour; see screen dumps). What tot do?

[Greg_S.]

Try updating the thumbnail on the selected photos. 

• Select the hourglass thumbnail(s) and press Ctrl+Shift+U; or
• Select the thumbnails and select Update thumbnail from the Edit menu

[default27975891fo5dct]

Thank you for your suggestion, but alas, it does not work. I selected a group of photo's, did the command, I saw the computer working, but no change in the representation. 

[Greg_S.]

Go to File>Manage Catalogs and try to Repair and Optimize the catalog.