Sasa posted a problem viewing Photoshop-Images (.psd) here. I have a similar problem.
In thumbnail mode I can see the preview image of Ulead PhotoImpact files (.UFO). When I open the same file
in the viewer or when moving the mouse over an .UFO-Image in listview no full Image or preview is shown.
Is this not supported or do I have to change some (plugin-)settings?
You are getting the thumbnails correctly because Opus is pulling them from the Shell Thumbnails extraction. But the internal Opus Viewer does not support .ufo files.