The time you are creating a smart preview of an image, are you able to see the option for " Original + Smart Preview" in the Library Module ?
And is it specific to only 1 image or all the images in Lightroom.
Where in the Library Module am I supposed to see "Original+Smart Preview"? I can't find it.
After supposedly creating the Smart Views, when I go the grid view in the Library Module, the thumbnails don't have the icon indicating that a Smart Preview exists, if this is what you mean.
It happens for all the images I tried it with.
Another observation: When I try to create a Smart Preview a second time, I get the message: "No Smart Previews were built. All Smart Previews were up to date".
So the time when you create a Smart Preview, you should be able to see " Original + Smart Preview " in the Grid view on the top right corner, in the Histogram.
OK, looks like we are getting somewhere:
I had the Histogram panel in the Library Module closed. When I opened it, it showed indeed "Original+Smart Preview" (after a little while).
When I switched now to the Development Module, there also "Original+Smart Preview" was shown. And for the photos without existing Smart Preview, I could now create the Smart Preview in the Development Module (which was not working before).
I did some more tests and it appears that when you start Lightroom with the histogram in the Library Module hidden, you get the errors I was having before.
If you open the histogram in the Library Module, everything seems to work.
So my conclusion for now: In order for the Smart Preview to work, leave the Histogram in the Library Module open....
If everything is working fine as you want, so you may leave the Historgram opened.
Yes, I can live with this workaround.