I did some disk house cleaning and maybe I moved something by mistake. I cannot get the preview window in the top left to show the results when I go to Library, Image Units and then select any of the listed items. Such as Gaussian Blur. It should be using the stock tif picture of the dolphins like the Filter directory is showing.
All the other categories are showing the previews as expected. And, there are two folders in the library list that say Image Units. One has the icon of dual film images and the other has the icon like Generators??
ImageUnits filters and generators are installed with the OS, not as part of Motion. The little previews you see in the Library are for the Motion-installed filters, generators, presets, etc, so the ImageUnits stuff doesn't have them.